Radio Acronyms 4000+ (Always under construction) By Hugh Stegman NV6H At end of file: Police/CB 10-codes Other police codes Computer networking standards [~] = not an acronym, just looks like one Radiospeak, techspeak, milspeak, NASAspeak, and compuspeak all developed for spoken, sent, or stored brevity. As Larry Van Horn is always noting, acronyms and abbreviations don't always save all that much space in written text. Utility Planet tries to slog through all the alphabet soup and write in good old English. Sometimes we fail. Decode our lapses thusly: Acronym Definition ------- ------------------------------------------------------- // Parallel transmission (simulcast) on -- /// Cloud layer below observing station +FC Tornado on the ground 1 LT first lieutenant 10-X "Ten-Ten," ten-meter amateur award 16-DPSK 16-Phase Differential Phase-Shift Keying 16P4A 16 phase, 4 amplitudes 2 LT second lieutenant 220SMA 220 (MHz) Spectrum Management Assn (Amateur) 2600 (1)2600 Hz, audio frequency used for US telephone idle tones 2600 (2)Hack/Phreak magazine, named in honor of above 2600 (3)Use of tone-spoofing equipment to control phone switches; now a good way to go to jail 2G Second Generation 2G ALE Second generation automatic link establishment 32BDA 32-Bit Disk Access (Windoze) 3D Three dimensional (like some weather models) 3F Three-figure code groups (mixed or all numbers) 3FG Three-figure code groups 3G Third Generation 3G ALE Third generation automatic link establishment 3GPP Third Generation Partnership Project 3G-TM Third Generation Traffic Management Protocol 3L Three-letter code groups 3LG Three-letter code groups 4F Four figure code groups (mixed or all numbers) 4FG Four figure code groups 4G Fourth Generation 4G LTE Fourth Generation - Long Term Evolution 4L Four-letter code groups 4LG Four-letter code groups 5 by 5 (1) Signal report: readability 5, strength 5 5 by 5 (2) Signal report: you are loud and clear 5D Demand Driven Direct Digital Dissemination 5F Five-figure code groups (mixed or all numbers) 5FG Five-figure code groups 5L Five-letter code groups 5LG Five-letter code groups 73 Old telegraphy slang: "Best regards" 81-81 Strange Russian teleprinting system, popular in Cuba 88 Old telegraphy slang: "Love and kisses" 89/336/EEC European electromagnetic compatibility directive 8-DPSK 8-Phase Differential Phase-Shift Keying 8P2A 8 phase, 2 amplitudes A Index 24-hour magnetic activity index, lower=better A (1)Altimeter setting A (2)Old "A" battery, for portable radio tube filaments A&P Airframe & Powerplant, U.S. aircraft mechanic certificate a/c Aircraft A/D Analog to digital converter A/G Air to ground A0 AM carrier with no modulation, now N0N A1 (Alpha-1) Aircraft maintenance status: no writeups; plane OK A1A Morse telegraphy for aural copy, i.e. "CW" A2 (Alpha-2) Status: write up non-mission-critical system A2A Modulated CW telegraphy for aural copy, i.e. "MCW" A3 (Alpha-3) Status: write up critical system; mission aborted A3E AM voice or broadcasting AA CW prosign: "[repeat] all after" AAA (1)Anti-Aircraft Artillery AAA (2)Authentication, Authorization and Accounting AAAS American Association for the Advancement of Science AAB Automatic Answer-Back (RTTY) AABCP Advanced airborne command post AAC Advanced Audio Coding AACC Airborne Air Command Center AADC Area Air Defense Commander AAF (1)Auxiliary Airfield AAF (2)Army Air Forces, obsolete AAFES Army and Air Force Exchange Service AAIC Accounting Authority Identification Code AAL ATM Adaptation Layer AAL-1 Synchronous adaptation layer designed for carrying voice trunk lines AAL-2 Adaptation layer intended for variable bit rate video, but never really got off the ground and is not offered by vendors AAL-3/4 Adaptation layer intended to be used by Frame Relay and SMDS and other delay-insensitive variable rate or bursty data traffic, but mostly now passed over in favour of AAL-5 AAL-5 'Simple and efficient adaptation layer' for computer networking AALC (1)Amphibious Assault Landing Craft AALC (2)Amplified automatic level control AAM Air to Air Missile AAMDS Automated Air Movement Data System AAMSS Arinc Aeronautical Mobile Satellite Service (proposed; would replace much of MWARA) AAR (1)Air to Air Refueling AAR (2)After-Action Review AAR (3)Automatic Alternate Rerouting AAR (4)Assn. of American Railroads AARS Army Amateur Radio System, started 1925, now part of MARS AASS Advanced Air Surveillance Radar AATO Automated Air Tasking Order AAV Assault Amphibious Vehicle AAVP Advanced Aircrew Vision Protection AAW Anti-Air Warfare AB (1)Air Base AB (2)CW prosign: "[repeat] all before" ABA Australian Broadcasting Authority ABAS Aircraft Based Augmentation System (GPS) ABC (1)Atomic, Biological, Chemical (warfare) ABC (2)American Broadcasting Company ABC (3)Australian Broadcasting Corporation ABCA American, British, Canadian, Australian ABCC Airborne battlefield command and control center ABCCC Airborne Command Control Center ABCS Army Battle Command System ABD Air Base Defense ABIS Advanced Battlespace Information System ABITS Airborne Imagery Transmission System ABL Airborne Laser ABM Anti-Ballistic Missile ABN Airborne ABNCP Airborne National Command Post ABO Annular Beam Oscillator ABOR Abort ABU Asia Broadcast Union AC (1)Alternating Current AC (2)Active Components (US Army) AC (3)Acquisition Center AC&I Acquisition, Construction & Improvement ACA (1)Airspace control authority ACA (2)Australian Communications Authority ACAA Automatic chemical agent alarm ACAP Application Configuration Access Protocol (computing) ACAPS Area communications electronics capabilities ACARS Aircraft Communications Addressing and Reporting System ACAS Airborne Collision Avoidance System ACAT Acquisition Category ACC (1)Air Combat Command (US) ACC (2)Area Communication Center ACC (3)altocumulus castellanus ACCHAN Allied Command Channel ACCINTNET ACC Intelligence Network ACCMSF Advanced Cooperative Collection Management ACCS Air Command and Control System ACE Airborne Command Element ACERT Army Computer Emergency Response Team ACF (1)Autocorrelation Factor ACF (2)Advanced Common Flightdeck ACFT MSHP aircraft mishap ACI Air Control Intercept ACINT Acoustic intelligence ACIS Air Combat Information System ACJ Advisory Circular, Joint ACK Positive Acknowledgment (ASCII 06) ACLS Automatic Carrier Landing System ACM (1)Association for Computing Machinery ACM (2)Advanced Cruise Missile ACM (3)Air Combat Maneuvering ACMI Air Combat Maneuvering Instrumentation ACOM U.S. Atlantic Command ACP (01)Allied Communication Publication (127, etc) ACP (02)Allied Communication Protocol ACP (03)Adjacent Channel Power ACP (04)Adjacent Channel Protection ACP (05)Access Control Point ACP (06)Access Control Protocol ACP (07)Access Communications Processor ACP (08)Achieved Communication Performance (ARINC) ACP (09)Adaptive Communications Processor ACP (10)Advanced Communications Package ACP (11)Alternate Command Post ACP (12)Airborne Command Post ACP (13)Area Command Post ACP (14)Automated Command Post ACP (14)Applied Communication Program ACP (15)Automatic Communications Processor ACP (16)Automatic Colt Pistol ACP (17)Autoloading Colt Pistol ACP100 Allied Call Sign and Address Group System - Instructions and Assignments ACP110 Tactical Call Sign Book ACP112 Task Organization Call Sign Book ACP113 Call Sign Book for Ships ACP117 Allied Routing Indicator Book ACP119 Allied Tactical Voice Call Sign System - Instructions and Assignments ACP121 Communications Instructions - General ACP122 Communication Instructions - Security ACP123 Common Messaging Strategy and Procedures ACP124 Communication Instructions - Radiotelegraph Procedure ACP125 Communication Instructions - Radiotelephone Procedure ACP126 Communication Instructions - Radioteletype Procedure ACP127 Communication Instructions - Tape Relay Procedures ACP127SUP1A Allied RATT Procedures (RTTY) ACP128 ALTERS Operating Procedures ACP129 Communications Instructions - Visual Signalling Procedures ACP130 Direction Finding Procedure ACP131 Communication Instructions - Operating Signals ACP134 Telephone Switchboard Operating Procedure ACP135 Communications Instructions - Distress and Rescue Procedures ACP136 Communication Instructions - Panel Signaling ACP147 Call Sign Book for Merchant Ships in Time of War ACP148 Allied Guide to Master ACP149 Radio Communication Instructions for Merchant Ships Under Naval Control ACP150 Recognition and Identification Instructions, Air, Land, and Sea Forces ACP160 IFF SIF Operational Procedures ACP165 Operational Brevity Codes ACP167 Glossary of Communications-Electronics Terms ACP168 Pyrotechnic Signals ACP176 Allied Naval and Maritime Air Communication Instructions ACP177 Land Forces Electronic Warfare Instructions ACP178 Maritime Electronic Warfare Instructions ACP179 Electronic Warfare Instructions for Air Forces ACP190 Guide to Frequency Planning ACP198 Instructions for the Preparation of Allied Communications Publications ACR Armored cavalry regiment ACRM Automated Communication Resource Manager ACRONYM Actual Computer Related Overused Name You Mention ACS (1)Assistant chief of staff ACS (2)Agile Combat Support ACS (3)Airborne COMINT System ACS (4)Attitude Control System ACSB Amplitude Compandored SideBand ACSL altocumulus standing lenticular cloud ACT Airborne Communications Terminal ACTD Advanced Concept Technology Demonstration ACTEX Active Controls Technology Experiments ACTIVE Advanced Controls Technology for Integrated Vehicles ACTS (1)Air Combat Training System ACTS (2)Automated Computer Time Service ACU Avionics Control Unit ACV Air Cushion Vehicle ACW Air Control Wing (like 552nd AWACS at Tinker) ADA (1)Americans with Disabilities Act ADA (2)Old computer language, not an acronym, named for Ada Babbage, the world's first programmer ADAS AWOS Data Acquisition System (Nice nested acronym) ADC Analog-to-Digital Convertor ADCC Air Defense Control Center addr Address ADDS Aviation Digital Data Service ADES Airdrop equipment and systems ADF (1)Automatic direction finding ADF (2)Australian Defence Forces ADIZ Air Defense Identification Zone ADM Admiral ADMD Administration Management Domain ADMIS Aircraft Departing at # Minutes Interval ADO (1)ActiveX Data Objects ADO (2)Active Data Objects ADOC Air defense operation center ADONIS Article Delivery Over Network Information Systems ADP Automated data processing ADPCM Adaptive differential pulse-code modulation ADPE Automated Data Processing Equipment ADPS ASARS Data Processing Station ADPSIS Automated Data Processing Software Inventory System ADPSO Automated Data Processing Security Officer ADPSSO Automated Data Processing System Security Officer ADR CW brevity: address ADRG ARC Raster Digitized Graphics ADS (1)Advanced Distributed Simulation ADS (2)Automatic Dependent Surveillance ADS-B Automatic Dependent Surveillance - Broadcast ADS-C Automatic Dependent Surveillance - Contract ADSI Air Defense System Integrator ADSL Assymetric Digital Subscriber Line Ae Auroral Electrojet magnetic activity index AEEC Airlines Electronics Engineering Committee AEOS Advanced Electro-Optical System Spectrograph AEPDS Advance Electronic Processing and Dissemination System AES (1)Advanced Encryption Standard AES (2)Application Environment Specification AES (3)Audio Engineering Society AEW&C Airborne Early Warning & Control AF (1) Air Force AF (2) Audio Frequency (30 Hz - 30 kHz) AFAMPE Air Force Automated Message Processing Exchange AFATDS Advanced Field Artillery Tactical Data System AFB Air Force Base AFC Automatic frequency control AFCA Air Force Communications Agency (US) AFCS Automatic Flight Control System AFDC Air Force Doctrine Center AFEPS ACARS Front-End Processor System (ground computer network) AFETR Air Force Eastern Test Range AFEWES Air Force Electronic Warfare Effectiveness Simulator AFFF Aqueous Film Forming Foam (fire fighting) AFFSA Air Force Flight Standards Agency AFGIHS Air Force Geographic Information Handling System AFGWC Air Force Global Weather Central at Offutt AFB, NE AFI (1)Africa/Indian Ocean (MWARA) AFI (2)Air Force Instruction (official directive) AFI (3)American Film Institute AFIT Air Force Institute of Technology AFIWC AF Information Warfare Center AFK Absolute Frequency Keying (amateur very slow Piccolo) AFKAI Air Force Cryptographic Aid, Recognition and Identification Systems AFMC Air Force Materiel Command AFMSS Air Force Mission Support System AFN American Forces Network (US broadcast for military) AFNET Air Force Integrated Telecommunications Network AFOS Automation of Field Operations and Services AFOSR Air Force Office of Scientific Research AFR Armed Forces Radio AFRES Air Force Reserve (US) AFRL Air Force Research Laboratory AFRN Armed Forces Radio Network AFRTS Armed Forces Radio & Television Services AFS (1)Air Force Station AFS (2)Aeronautical Fixed Service AFSAA AF Studies and Analysis Agency AFSATCOM Armed Forces Satellite Communication AFSFC Air Force Space Forecasting Center AFSFCR AF Space Forecast Center Replacement AFSK Audio frequency-shift keying AFSOC Air Force Special Operations Command AFSOF Air Force Special Operations Forces AFTCO Air Force Telecommunications Certification Office AFTN Aeronautical Fixed Telecommunication Network AFV Alternate Fuel Vehicle AFW Air Force Weather AFWSS Air Force Weather Support System AFWTF Atlantic Fleet Weapons Training Facility AG (1)Adjutant general AG (2)Airlift Group AGC Automatic gain control AGE Aerospace Ground Equipment (pronounced like how old you are; when you replace it you order New Age) AGL (1)Above ground level AGL (2)Air to Ground Laser AGM Air to Ground Missile AGU American Geophysical Union AGWPE AGW Packet Engine (creator: SV2AGW) Ah Ampere-hour(s), battery capacity AH Authentication Header AHAMSL Antenna height above mean sea level AHD Acoustic Hailing Device AHDL Analog Hardware Descriptive Language AHF Adaptive High Frequency AHMSL Antenna height above mean sea level AHP Army Heliport AI (1)Artificial intelligence AI (2)Air Interdiction AI (3)Airborne Interceptor AI (4)Avionics Infrastructure AIA Air Intelligence Agency AIC Air Intercept Control AICPITS All India Coordinated Program of Ionosphere & Thermosphere Studies AIDA Atmospheric Investigations of Dynamics over Arecibo AIDC (1)Air Traffic Services Interfacility Data Communication AIDC (2)Automatic Identification and Data Capture AIFSS Automated International Flight Service Station AIG (1)Address Indicator Group AIG (2)Air Intelligence Group AIM (1)Air launched Interceptor Missile AIM (2)AOL Instant Messenger (popular internet talk program) AIN Advanced Intelligent Network (US NCS) AIR (1)All-India Radio AIR (2)Aviation Incident Response (Red Cross) AIREP Air Report; weather observation, like a PIREP AIRES Advanced Imagery Requirements and Exploitation System AIRK Area interswitch rekey AIRFL Aerial Refueling AIRMET Air Meteorological Information AIRST Advanced Infrared Search and Track AIS (1)Automatic Identification System (USCG) AIS (2)(Universal) Automated Identification System AIS (3)Alarm Indication Signal AJ Anti-Jam AJCOM Anti-Jam Communications AkDT Alaskan Daylight Time, US AkST Alaskan Standard Time, US AL Approach and landing ALARM Air-Launched Anti-Radiation Missile ALC (1)Automatic level control ALC (2)Air logistics center ALC Air Logistics Center ALCC (1)Airborne Launch Control Center ALCC (2)Airlift Coordination Cell ALCE Airlift Control Element ALCF Airlift Control Flight ALCM Air Launched Cruise Missile ALCS (1)Airlift Control Squadron ALCS (2)Airborne Launch Control System ALE Automated Link Establishment ALERT Attack & Launch Early Reporting to Theater ALF Absorption Limiting Frequency, realtime version of LUF AlGaN Aluminum-Gallium Nitride ALOC Air lines of communication Aloha Wide-area net protocol, developed at U of Hawaii ALP airport location point lpha + # Aircraft maintenance status (1 is best) Alpha Hotel A-- H--- (also Adam Henry) ALQA Active Link Quality Analysis ALS (1)Advanced Life Support ALS (2)Airlift squadron ALTERS Allied Telecommunications Record System ALTRV Altitude Reservation ALU Arithmetic Logic Unit (computer h/w) ALW Airlift Wing AM (1)Amplitude Modulation AM (2)Aeronautical Mobile AM (3)Ante Meridian, hours between midnight and 11:59 local AMARC Association Mondiale des Radiodiffusuers Communautaires AMASS Airport Movement Area Safety System AMBALG Algerian Embassy AMBE Advanced Multi-Band Excitation AMC (1)Air Mobility Command (old Air Force MAC, MATS) AMC (2)Army Materiel Command (US) AMCC Air Mobility Control Center AMCLD Active Matrix Liquid Crystal Display AMCO Aircraft maintenance company AMCS Air Mobility Control Squadron AMD (1)American Micro-Devices (with Cyrix, Intel's competition) AMD (2)Automatic Message Display AMDRFM Advanced Monolithic Digital Radio Frequency Memory AME (1)Automatic Message Exchange AME (2)Air Mobility Element AME (3)Amplitude modulation equivalent AMEDD Army Medical Department AMHS (1)ATS Message Handling System AMHS (2)Aeronautical Message Handling System AMI Alternate Mark Inversion AMMCS Airborne Multimedia Multiservices Communication System AMO Air & Maritime Operations AMOC Air & Maritime Operations Center (CBP) AMOG Air Mobility Operations Group AMOS Air Force Maui Optical Site AMP Antenna Maintenance Program AMPS (1)Advanced Mobile Phone Service (analog, obsolete) AMPS (2)Automated Mission Planning System AMRAAM Advanced Medium-Range Air-to-Air Missile AMRAD Amateur Radio Research And Development Corporation AMRS Austrian Military Radio Society AMS Analog Mixed Signal AMSA Australian Maritime Safety Agency AMSAT Radio Amateur Satellite, Inc. AMSI Arctic Maritime Safety Information AMSS Aeronautical Mobile Satellite Service AMTOR Amateur Teleprinting Over Radio (Ham SITOR) AMVER Automated Mutual Assistance Vessel Rescue System AMW Air Mobility Wing AMX Air Mobility Express AN Army/Navy (prefix on US military type designators) AN/FRT Army/Navy Fixed Radio Transmitting AN/GRC Army/Navy General Radio Communication AN/MRC Army/Navy Mobile Radio Communication ANARC Assn. of North American Radio Clubs ANDVT Advanced Narrowband Digital Voice Terminal ANG Air National Guard ANGB Air National Guard Base ANI Automatic Number Identification ANL Automatic noise limiter ANMCC Alternate National Military Communications Center (?)-WAR 46 Annmt Announcement Annr Announcer ANS (1)Air Navigation Services ANS (2)Advanced Network Services, operates an Internet backbone ANSI American National Standards Institution ANSP Air Navigation Service Provider ANT (1)Antenna [~] ANT (2)Advantaged Node technology ANZUK Australia, New Zealand, United Kingdom (alliance) ANZUS Australia, New Zealand, United States (alliance) AO Area of operations AO1 automated station without precipitation discriminator AO2 automated station with precipitation discriminator AOA (1)Angle Of Arrival AOA (A)ACARS Over AVLC (ARINC, neat nested acronym) AOC (1)Air Operations Center AOC (2)Army Operations Center (Pentagon) AOC (3)Air Operational Control AOC (4)Aeronautical Operational Control Communications AOE Airport of Entry AOI Area Of Interest AOO Area of operations AOR (1)Area of responsibility AOR (2)Atlantic Ocean Region (USCG GMDSS) AOV ACARS Over VDL (ARINC, neat nested acronym) AOS (1)Acquisition Of Signal AOS (2)Area Of Service Ap Planetary A index of geomagnetic activity AP (1)Access Point AP (2)Associated Press APC Armored personnel carrier APCO Association of Public Safety Communications Officials APCO 25 Project 25 (P25), Standard for digital public safety radio API Application Programming Interface (computers) APIC APCO Project 25 Interface Committee APIPA Automatic Private Internet Protocol Addressing APL A Programming Language (computer code) APLink Amtor-Packet Link APNIC Asia Pacific Network Information Centre APO (1)Air Post Office APO (2)Army Post Office APOD Aerial port of debarkation APOE Aerial port of embarkation APPCON Approach Control [~] APREQ Approval Request [~] APRNT apparent APRS (1)Automatic Position Reporting System, ham tracking w/GPS APRS (2)Automatic Packet Reporting System APRX approximately APSC APCO Project 25 Steering Committee APT Automatic Picture Transmissions APU Auxiliary Power Unit APV Approach with Vertical Guidance APVL Approval [~] AQC Automatic Quick Call AR (1)Aerial refueling AR (2)Ground track for above AR (3)CW prosign: "End of message" AR (4)Army Regulation AR (5)Activity Request ARA Appletalk Remote Access, Mac networking ARB Air Reserve Base ARC (1)American Red Cross ARC (2)Airborne Radio Communications (AN/ARC-xxx) ARC (3)Air Reserve Component ARC-190 Common Collins mil HF aircraft radio, civil version is HF-190 ARC-220 Fancy Collins HF radios for new US mil aircraft ARC-230 Collins 400-watt HF Link-11/Tadil-A aircraft radio, civil voice version is HF-121 ARCAL Aircraft Radio Control of Aerodrome Lighting Archie Internet database search program, finds files ARCP Air Refueling Control Point ARCS Automatic Radio Control System (NATO) ARD Automatic Ring Down ARDF (1)Automatic Radio Direction Finding ARDF (2)Amateur Radio Direction Finding AREC (1)Air resource element coordinator AREC (2)Amateur Radio Emergency Corps, now ARES ARES Amateur Radio Emergency Service ARF Air Reserve forces ARFA Allied Radio Frequency Agency ARFOR Army forces ARG (1)Amphibious Ready Group ARG (2)Air Refueling Group ARGOS Advanced Research and Global Observation Satellite ARIA Advanced Range Instrumentation Aircraft ARIB Association of Radio Industry Businesses (Japan) ARIDPCM Adaptive Recursive Interpolated Differential Pulse Code Modulation (whew!) ARIN American Registry for Internet Numbers ARINC Aeronautical Radio, Inc (US radio consortium) ARIP Air Refueling Initial Point ARISS Amateur Radio on the International Space Station ARM Anti-Radiation Missile ARMER Allied Radio Matrix for Emergency Response ARMRV (1)Armored Mobile Reconnaissance Vehicle ARMRV (2)Armored Multi-Role Vehicle ARNG Army National Guard ARO Army Research Office ARP Address Resolution Protocol, Internet ARPA Advanced Research Projects Agency, operated original Internet ARPANET ARPA Network, became NSFNET, now separate from Internet ARQ Synchronous transmission and automatic repetition teleprinter system ("Acknowledge Request") ARQ6-90 Six-character blocks simplex ARQ teleprinter system ARQ-E3 Single channel ARQ teleprinter system ARRL American Radio Relay League ARRS Aerospace Rescue and Recovery Service ARS Amateur Radio Service ARSA (1)Airborne Reconnaissance and Surveillance Architecture ARSA (2)Airport Radar Service Area ARSOF Army special operations forces ARTCC Air Route Traffic Control Center ARTE (1)French media company ARTE (2)ADA Run Time Environment ARTG Amateur Radio Teleprinter Group (Swiss) ARTS Automated Remote Tracking Station ARW Air Refueling Wing (USAF/AFRES) ARWO Aerial Reconnaissance Weather AS (1) Air station AS (2) CW prosign: "Please Wait" AS (3) Analog secure (like original PARKHILL) AS (4)Submarine Tender (USN) ASA American Standards Association, obsolete ASAM Anti-Shipping Activity Message (warning) ASAP As Soon As [humanly] Possible; how one handles FLASH traffic ASAR Advanced Synthetic Aperture System ASARS Advanced Synthetic Aperture Radar System ASAS All Source Analysis System (US Army) ASAS-RWS ASAS Reconfigurable Work Station ASAT Antisatellite ASB Aviation support battalion ASC (1)AUTODIN Switching Center ASC (2)Accredited Standards Committee (ANSI) ASC (3)American Society of Cameramen (motion picture) ASC2A Air & Space Command & Control Agency ASCC Army service component command ASCIET All Services Combined Identification Evaluation Team ASCII American Standard Code for Information Interchange, 7-bit computer alphabet, usually extended to use 8th bit ASCOT Air Support Command Operations Task (RAF Air Transport) ASD Assistant Secretary of Defense ASDE-3 Airport Surface Detection Radar System ASDS Advanced SEAL Delivery System (a minisub; see SEAL) ASEAN Association of South East Asian Nations (old SEATO) ASECNA Agence pour la Securite de la Navigation Aerienne en Afrique et a Madagascar ASF Advanced Systems Format (Microsoft media player) ASG (1)Aeronautical Standards Groups ASG (2)Area support group ASIC Application Specific Integrated Circuit ASID Advanced Secure Information Dissemination ASIM Automated Security Incident Measurement ASIO Australian Security Intelligence Organisation ASIT Adaptable Surface Interface Terminal ASK Amplitude Shift Keying ASL (1)Above Sea Level ASL (2)Active Stations List (Enigma 2000) ASLAR Aircraft Surge Launch and Recovery ASM (1)Air to Surface Missile ASM (2)Analog Switching Module ASM (3)Assembler (computer code) ASMB Area support medical battalion ASMC Area support medical company ASME American Society for Mechanical Engineers ASMRO Armed Services Medical Regulating Office ASO Air surveillance officer ASOC Air Support Operations Center ASOS Automated Surface Observation System ASOTSE Army special operations theater support element ASP (1)Ammunition supply point ASP (2)Acquisition Support Plan ASP (3)Active Server Pages ASP (4)Application Service Provider ASP (5)Aeronautical Surveillance Panel ASPECT Airborne Spectral Photometric Environmental Collection Technology ASR (1)Automatic Send-Receive ASR (2)Airport Suveillance Radar Assn Association Assoc Association AST Atlantic Standard Time, Canada ASTM American Society for Testing and Materials ASU Aircraft Starting Unit ASW Anti-submarine warfare AT (1)Advanced Technology (IBM's original name for its improved PC, now a standard architecture) AT (2)Amateur (radio allocation code) ATA (1)Army Technical Architecture ATA (2)AT Attachment ATA (3)American Trans Air ATAPI AT Attachment Packet Interface ATC Air Traffic Control ATCALS (1)Air Traffic Control and Landing System ATCALS (2)Air Traffic Control Liaison Section ATCCS Army Tactical Command & Control System ARCRBS Air Traffic Control Radar Beacon System ATCS Advanced Train Control System ATCT airport traffic control tower ATD Advanced Technology Demonstration ATDL 1 Army Tactical Data Link 1 ATF Advanced Tactical Fighter ATF Bureau of Alcohol, Tobacco & Firearms ATH Air Transportable Hospital ATG Afloat Training Group (USN) ATHS Automatic Target Hand-off System ATIS Automated Terminal Information System (usually voice loop) ATM (1)Asynchronous Transfer Mode, 53-byte packets ATM (2)Air Traffic Management ATM (3)Automated Teller Machine ATM (4)Advanced trauma management ATMs Air Tasking Messages ATN (1)Aeronautical Telecommunication Network ATN (2)Adventist Television Network ATO (1)Air Tasking Order ato (2)Abort To Orbit ATOI Aerial Track Of Interest A-TOR Automated Telex Over Radio ATP (1)Ammunition transfer point ATP (2)Appletalk Transaction Protocol, Mac networking ATP (3)Acquisition, Tracking & Pointing ATP (4)Authority to Proceed ATP (5)Air Traffic Procedures ATR Air Transport Rack (standard airplane radio bay) ATR/ATC Automatic Target Recognition/ Automatic Target Correlation ATS (1)Aeronautical Telecommunications Services ATS (2)Air Traffic Services ATS (3)Applications Technology Satellite ATSA Aviation and Transportation Security Act ATSC Advanced Television Systems Committee (US Digital TV) ATSC-H Handheld ATSC (for cell phones, also ATSC-M) ATSU Air Traffic Service Unit ATU (1)Antenna Tuning Unit ATU (2)Arab Telecommunications Union ATU (3)African Telecommunications Union ATU-80 SITOR alphabet allowing transmissions in Arabic ATU-A Arabic ATU-80 alphabet ATV (1)Amateur (fast-scan) television ATV (2)All-Terrain Vehicle AUI Attachment Unit Interface, Ethernet AUSREP Australian Ship Reporting System AUTO Weather observation is from automated station [~] AUTOCONET Automatic Digital Network Conference Network AUTODIN Automatic Digital Network (US military) AUTOVON Automatic voice network (now DSN as of 1990) AUV Autonomous Underwater Vehicle AUW All Up Weight (gross) AV Air Vehicle AVANA Altitude reservation Void, Not Airborne [time] AVC Automatic volume control AVHRR Advanced Very High Resolution Radiometer AVI Audio Video Interleave (Microsoft file format) AVIM Aviation intermediate maintenance AVL Automatic Vehicle Locating AVLC (1)Aviation VHF Link Control AVLC (2)Automatic Vehicle Location and Control AVN AViatioN weather model AVO Air Vehicle Operator AVTR Airborne Video Tape Recorder AVUM Aviation unit maintenance AWACS Airborne Warning And Control System AWADS Adverse Weather Aerial Delivery System AWAPS Automated Weather Distribution System AWDS Adverse Weather and Debriefing System AWG American Wire Gauge AWGN Arbitrary White Gaussian Noise AWIPS Advanced Weather Interactive Processing System awk Aho, Weinstein & Kernighan, wrote a Unix script language AWN Aviation Weather Network, now on US Air Force Digital Weather Switch AWO American Waterway Operators AWOL Absent without leave AWOS Automated Weather Observing System AWR Adventist World Radio AWS (1)Air Weather Service AWS (2)Advisory Warning System AWS (3)Automated Weather Systems AWS (4)Automated Weather Station AWST Automated Weather Station AX.25 Amateur variant of CCITT X.25 packet radio protocol B (1)began B (2)old "B" battery for tube plates, typically 90 volts B&G Bombing & Gunnery B/m Benchmark B/U Backup B+ Tube plate voltage (highest in set) B8E Mode: Independent sideband, different voice programs B9W Mode: Independent sideband, mixed voice & data modes BA Braking action BAA (1)Broad Agency Announcement BAA (2)Broad Area Announcement BAC Broad Area Coverage BAe British Aerospace Bae British Aerospace BAI Backup Aircraft Inventory BAI Battle Area Interdiction Balun Balanced-to-unbalanced line transformer [~] BAM Beta and Advection Model (wx) BAN Base Area Networks BANANA Build Absolutely Nothing Anywhere Near Anyone (municipal response to most radio proposals) BAQ Basic allowance for quarters Baro-VNAV Barometric Vertical Navigation BAS Basic allowance for subsistence BASIC Beginners' All-Purpose Symbolic Instruction Code, computer language BAT (1)Blood Alcohol Testing (the "Batmobile," in the field) BAT (2)File extension: execute as command list (Batch job) BAT (3)Brilliant Anti-armor Submunition Baud Computer transmission unit, one state transition per second, no longer one bit per second in complex modulation schemes BBC British Broadcasting Corporation BBCS Broadband Connectivity Service (Swisscom) BBIS Battle Broadcast Information System BBN Backbone network BBS (1)Bulletin Board System (computer networking) BBS (2)Battery backup system BC (1)Broadcast BC (2)Back course BC (3)Patches (of sig. Weather) BC2A Bosnia Command & Control Augmentation BC3 Battle management and command, control and communications BCA Broadcast Control Authority BCB Broadcast Band (typically 540-1710 kHz) BCC (1)Base Communication Center BCC (2)Bureau Communication Center (LAPD) BCC (3)Battlefield circulation control BCC (4)Blind Carbon Copy (e-mail) BCD (1)Binary-coded decimal BCD (2)Bad conduct discharge BCE Base civil engineer BCF Backup communications facility, Dahlgren, VA BCFG Fog patches BCI (1)Broadcast interference (from xmtr to bc) BCI (2)Binary-coded information BCL (1)Broadcast listener BCL (2)Broadcast Communications Limited (New Zealand) BCM Baseline correlation matrix BCO (1)Base communications officer BCO (2)Base contracting officer BCO (3)Broad concept of operations BCP (1)Base communications package BCP (2)Base comprehensive plan BCS Broadcast Keying Station BCT Battlefield Communications Terminal bd Baud BDA (1)Battle damage assessment BDA (2)Bermuda (NASA) BDAR Battle damage assessment and repair bde Brigade BDU (1)HFDL: Basic Data Unit BDU (2)Battle dress uniform BEAR Beam Experiment Aboard Rocket BEC Bulk encrypted communications BEE Russian FSK mode, apparently not an acronym BEEF Base Engineering Emergency Force ("Prime BEEF team") BEL Bell (ASCII, RTTY) Bel Unit of voltage or power ratio, named for Alexander Graham Bell, usually expressed in deciBels BEP (1)Bit error probability BEP (2)break-even point BER Bit Error Rate BERT (1)Bit error rate test(er) BERT (2)Bit Error Rate Testing BF Basic Function BFACS Battlefield Functional Area Control Systems BFBS British Forces Broadcasting Service BFO (1)Beat frequency oscillator (CW/SSB mode of receiver) BFO (2)Backhaul follow-on BFSK Binary Frequency-Shift Keying BG Brigadier general BGEN Brigadier general BGP Border Gateway Protocol (TCP/IP) BICE Bureau of Immigration and Customs Enforcement BID Billing Identifier BIDDS Base integrated digital distribution system BIDS Backup information display system BIFC (1)Boise Interagency Fire Cache, obsolete BIFC (2)Boise Interagency Fire Center, now NIFC BiFET Bipolar Field Effect Transistor BIH Bureau International l'Heur, International Time Bureau, coordinates UTC leap seconds BIIS Binary Interchange of Information and Signaling BILS Ballistic Impact Locator System Bin Binary BIND (1)Berkeley Internet Name Domain BIND (2)Berkeley Internet Name Daemon (old) BIND (3)Buggy Internet Name Daemon (geekspeak) Binhex Binary to hexadecimal, usually for sending binaries as ASCII BIOS Basic Input/Output System (part of computer op-system) BIOT British Indian Ocean Territory BIP Base Information Protect BIPS (1)Billion Instructions per Second (computing) BIPS (2)Backup Impact Prediction System BIPS Billion Instructions Per Second B-ISDN Broadband-Integrated Services Digital Network BIST Built-In-Self-Test Bit (1)BInary digiT, a one or zero, basic digital information unit BIT (2)Built-In Test BIT Built in Test Bit/s Bit per second BITE Built-In Test Equipment BITNET Because It's Time NETwork, from IBM, now global BIU Bus interface unit (computer h/w) BK CW prosign: long break or break-in BKN Broken cloud cover BL (1)Baseline BL (2)blowing BLAISE (1)British Library Automated Information Service BLAISE (2)Blaise Pascal, French Mathematician BLDU Blowing dust BLER Block Error Rate BLERT Block Error Rate Testing BLEVE Boiling Liquid Expanding Vapor Explosion BLM Bureau of Land Management (US) BLOS Beyond line of sight BLPY Spray BLS Bureau of Labor Statistics (US) BLSA Blowing sand BLSN Blowing snow BM Battle Management BMC2 Battle Management, Command and Control BMC3 Battle Management, Command, Control and Communication BMC3I Battle Management C3I BMC4ISR Battle Management C4I Surveillance and Reconnaissance BMD Ballistic Missile Defense BMDATC Ballistic missile defense advanced technology center BMDC Ballistic Missile Defense Center BMDCCC Ballistic missile defense command and control center BMDE Ballistic missile defense enhancement BMDO Ballistic missile defense organization, formerly SDIO BMDOC Ballistic missile defense operating center BMDSCOM Ballistic Missile Defense Systems Command, now U.S. Army Strategic Defense Command BMEWS Ballistic Missile Early Warning System BMO Ballistic Missile Office (US) BMOPS Battle Management Operations BMP (1)File extension: bitmap image BMP (2)Battle manager processor BMS Backward Music Station (weird RF feedback on HF) BMT (1)Ballistic Missile Threat BMT (2)Beam Management Terminal BMT (3)Bronx Motor Transit BMT (4)Ballistic Missile Technology BMT/SS Ballistic Missile transporter, storage and shipping bn Battalion BN CW prosign: repeat between -- and -- BNC (1)Bayonet Neill-Concelman (cable connector) BNC (2)Bayonet Navy Connector (alternate) BNC (3)Blimped Noiseless Camera (Classic Mitchell) BNCC Base Network Control Center BNCR Blimped Noiseless Camera, Reflex BnOC Battalion Operations Center BNSC British National Space Center BO Bad Order (inoperative unit writeup) BoD Board of Directors BOM Bureau Of Meteorology (Australia) BOND Beginning Of Next Day BOOTP Bootstrap Protocol (IP addressing) BOPS Billion operations per second (computing) BOQ Bachelor Officer Quarters BORAM Block-Oriented RAM BOSS Battlefield Optical Surveillance System BOT Beginning of Tape bot Robot, typically a network program that does an admin duty BP Bandpass BPI Boost-Phase Intercept BPL Broadband over Power Line bpp bits per pixel bps Bit per second, not necessarily a "baud" Bps Bytes per second BPSK Biphase Shift Keying BQ (1)Beam Quality BQ (2)Acknowledging receipt (DSC protocol) BR Bridgewire resistance BR mist BRAC Base Realignment And Closure BRACC Base Realignment And Closure Commission (US military) BRB Be Right Back (Internet) BRD Broadcast brdg bridge BRI Basic Rate Interface BRI Basic Rate ISDN, 2 64Kbps channels BRV (1)Booster Recovery Vessel (NASA) BRV (2)Ballistic reentry vehicle (Stratcom) BS (1)Battle staff BS (2)Battle station BS (3)Backspace BS (4)aka "Bravo Sierra;" the excrement of bulls BSA (1)Brigade support area BSA (2)Birmingham Small Arms BSC Base security council BSD Berkeley Software Distribution (Unix type) BSE Broadcast Satellite Experiment BSKSA Broadcasting Service of the Kingdom of Saudi Arabia BSS (1)Broadcast Satellite System BSS (2)Broadcasting Satellite Service BSSC Battle staff support center BSTRS Base Support Trunked Radio System, aka "B-STARS" BSU (1)Baseband separation unit BSU (2)Bulk Storage Unit BSVS Backup Secure Voice System BT (1)("Bravo Tango") Bomb threat BT (2)CW prosign: short break BT (3)British Telecom BTC Block transfer controller (computing) BTH Below (beyond) the horizon BTI British Telecom International BTL Black telemetry (USAF) Btry Battery BTS Broadcast Transmitting Stations BTW By the way Buff Big Ugly Flying F[ellow] (B-52) BUFR Binary Universal Format for Representation BULLDOG BULLSEYE US Navy HF upgrade, like USAF's SCOPE, but includes DF [~] BUMCS Backup Master Control Station (GPS, Gaithersburg, MD) BUR Bottom Up Review BURN 1000W UHF aircraft orderwire (US mil; not an acronym, refers to high power) BVR Beyond Visual Range BVR Beyond visual range BW (1)Bandwidth BW (2)Biological Weapon BWC Bandwidth Compression BWS Base weather station BX Base exchange BZ ("Bravo Zulu") Good job C (1)Capacitance, in farads C (2)Confidential C (3)the C programming language; also C+ and C++ C (4)Celsius C (5)Designator for head of British MI6 C (6)Center (with reference to runway designation) c The speed of light, and radio waves, in a vacuum C&DH Communications & Data Handling C&DP Communications & Data Processing c/s Callsign c/w Callword C2 Command and Control C2CM Command and Control Countermeasures C2IPS Air Mobility Command and Control Information Processing System C2P Command and Control Processor C2PC Command & Control Personal Computer C2V Command and Control Vehicle C2W Command and Control Warfare C2WC Command and Control Warfare Commander (US Navy) C3 Command, Control and Communications C3F Mode designation: television or video C3I Command, Control, Communications and Intelligence C3S Command, control and communications segment C3SMP Command, control and communications system master plan C4FM Continuous four-level Frequency Modulation C4I Command, Control, Communications, Computers and Intelligence C4ID Command, Control, Communications, Computers and intelligence Dissemination C4IFTW C4I for the Warrior C4ISR Command, Control, Communications, Computing, Intelligence, Surveillance, & Reconaissance C4S Command, Control, Communications, Computer Systems C4SMP Command, control, communications and computers system master plan CA (1)civil affairs CA (2)COMSEC Account CA (3)cloud-air lightning CA (4)Counter Air CA (5)Cyanoacrylate (Super Glue) CAATS Canadian Automated Air Traffic System CAB Combat Area Broadcast CACS Command And Control Squadron CAD (1)Computer-aided design CAD (2)Coherent amplitude detector CAD (3)Computer-aided dispatch CAD/CAM Computer aided design/computer aided manufacturing CADRG Compressed Arc Digitized Raster Graphics CAE (1)Common Application Environment CAE (2)Computer Aided Engineering CAEWIS Computer Aided Electronic Warfare Information System CAF Combat Air Forces CAFWSP CAF Weather Support Package CAI (1)Common Air Interface CAI (2)Computer-aided instruction CAI (3)Cooperative Airborne Identification CAINS Carrier Aircraft Inertial Navigation System CAL Calibrate, calibration CALLS Contact And Long-range Liaison System (USCG) CALM Codan Automated Link Management CALS (1)Computer-aided Acquisition & Logistics System CALS (2)Contingency Airfield Lighting System CAM Computer-aided manufacturing camo Camouflage CAMO Computer-aided manual operation CAMS Communications Area Master Station (USCG, obsolete) CAMSLANT Communications Area Master Station, Atlantic; obsolete CAMSPAC Communications Area Master Station, Pacific; obsolete CAN (1)Cancel (ASCII) CAN (2)Controller Area Network (industrial automation) CANFORCE Canadian Forces CANR Canadian NORAD Region CANSO Civil Air Navigation Services Organization CANUS Canada/US CAOC (1)Combined Air Operations Center CAOC (2)Combined Allied Operations Center, Vicenza, IT (Allied Force) CAP (1) Civil Air Patrol CAP (2) Carrierless Amplitude Phase CAPCOM Capsule Communicator (NASA) CAPE Convective Available Potential Energy (WX) CAPEG Cape Canaveral Ground Antenna (GPS) CAPPS Computer Assisted Passenger Prescreening System CAPS Center for the Analysis and Prediction of Storms (NWS) CAPT Captain CAR Caribbean (MWARA) CARB (1)Channel Availability Radio Bulletin (NATO) CARB (2)Channel Availability and Receipt Broadcast (NATO) CARCAH Chief, Aerial Reconnaissance Coordination, All Hurricanes (NHC) CARF Central Altitude Reservation Facility (FAA) CARIBROC Caribbean Regional Operations Center CARR Corrective Action Request & Report CAS (1)Close Air Support CAS (2)Collision Avoidance System CAS (3)Calibrated Air Speed CASE (1)Common automated system execution CASE (2)Computer-aided software engineering CASE (3)Computer-aided system engineering CASREP Casualty Report CAT (1)Clear Air Turbulence CAT (2)Computer Aided Transceiver, proprietary control interface CAT (3)Communications Assist Team (USCG) CATIS Computer Aided Tactical Information System CATT Computer Assisted Technology Transfer CATV Community Antenna Television ("cable") CAU Crypto Ancillary Unit CAV (1)Collision Avoidance CAV (2)Conditionally Available (LA City FD) CAV (3)Ceiling and visibility CAVOK Ceiling & Visibility OK (non-US METAR) CAVU Ceiling & visibility unlimited CB (1)Citizen Band Radio (legal or otherwise, around 27 MHz) CB (2)Cumulonimbus (thundercloud) CBAA Community Broadcasting Association of Australia C-band 4-8 GHz microwave band CBC Canadian Broadcasting Company CBFS Cesium Beam Frequency Standard CBM Central battle management CBMAM Cumulonimbus mammatus cloud CBP Customs and Border Protection CBR (1)Chemical, Biological, Radiological (warfare) CBR (2)Constant bit rate CBRN Caribbean Basin Radar Network CBS Columbia Broadcasting System (U.S.) CBT (1)Computer-based training CBT (2)Combat CBTS Computer-based training system CBU Cluster Bomb Unit CBW (1)Chemical & Biological (warfare) CBW (2)Constant bandwidth CC (1)Transmission is in Standard Chinese ("Mandarin") CC (2)Command & Control CC (3)Command Center CC (4)Control Center CC (5)Commander CC (6)Computer controller CC (7)Copies CC (8)C Compiler (unix) CC (9)cloud-cloud lightning CC&D Camouflage, concealment and deception CC&R Covenants, Conditions & Restrictions; what you check before buying a home if you intend to build an antenna there CCAS Cape Canaveral Air Station, FL, formerly CCAFS CCB (1)Configuration Control Board CCB (2)Computer Controlled Brake (railroad) CCC (1)Central computer complex CCC (2)Communications control complex CCC (3)Consolidated Command Center (NORAD) CCD Charge Coupled Device CCDM Consultative Committee for the Definition of the Meter CCDS Consultative Committee for the Definition of the Second CCDS Command Center Display System CCE (1)Command & control element CCE (2)Consultative Committee on Electricity CCEMRI Consultative Committee for Ionizing Radiations CCG Calibration Coordination Group CCIP Continuously-Computed Impact Point CCIR International Radio Consultative Committee, now ITU-R CCIR 476-4 International SITOR character set CCIR 493-44 FSK 100/170 Selcall, AKA Codan 8580 CCIRID Charge-coupled infrared imaging device CCITT Comite Consultatif International de Telegraphique et Telephonique (International Telegraph & Telephone Consultative Committee), obsolescent CCL Common Command Language CCM (1)Combined Cipher Machine (WWII Allies) CCM (2)Counter-Countermeasures CCMC Canadian Centre for Maritime Communications CCP Console Command Processor, part of CP/M CCPC Civil Communications Planning Committee (NATO) CCPDS-R Command Center Processing and Display System - Replacement CCR Central Control Room CCRP Continuously-Computed Release Point CCS (1)Continuous Commercial Service (power rating) CCS (2)Charge Control System CCSL cirrocumulus standing lenticular cloud CCT Computer Compatible Tape ccTLD Country Code Top Level Domain CCTV Closed Circuit Television C-cubed Command Control and Communications CCV Code change verifier CCW (1)Counter-clockwise CCW (2)Command & Control Warfare CCW (3)Continuous Carrier Wave CCW (4)Coherent CW CCW (5)Class C CW biasing (most efficient) CD (1)Compact Disc CD (2)Civil Defense (now FEMA in US) CD (3)Carrier detect (modem line) CD (4)Collision Detection (networking) CDA (1)Central distribution amplifier CDA (2)Command & data acquisition CDB Command data buffer CDC (1)Canadian Department of Communications CDC (2)Centers for Disease Control (US) CDC (3)Control Data Corporation CD-DA Compact Disc Digital Audio (format, part of the "Red Book") CDE Common Desktop Environment CDF (1)Common Data Format CDF (2)California Division of Forestry (fire fighters) CDHF Central Data Handling Facility CD-I Compact Disc - Interactive (one format in the "Green Book") CDIS Canadian Defence Intelligence Staff CDL Common Data Link CDM Chemical Downwind Message (US Army) CDMA Code Division Multiple Access CDMA One (IS-95) Qualcomm 2nd generation CDMA CDMA2000 3G CDMA technology CDNU Control Display Navigation Unit CDPD Cellular Digital Packet Data CDR (1)Commander CDR (2)Command destruct receiver (Stratcom) CD-R Compact Disc - Recordable CDRAM Cache Dynamic Random Access Memory CD-ROM Compact Disc Read Only Memory CD-ROM XA CD-ROM eXtended Architecture, extends the "Yellow Book" CD-RTOS Compact Disc - Real Time Operating System (CD-I) CDS (1)Canadian Defence Staff CDS (2)Combat Direction System CDT Central (US) Daylight Time CDTI Cockpit Display of Traffic Information CDU Control display unit (fancy "control head") CE (1)Conformite Europeanne (European Conformity); mark put on products for EEC CE (2)Committee that sets these requirements CEC (1)Commission of the European Communities (drafts "CE" standards) CEC (2)Cooperative Engagement Capability CECOM US Army Communications Electronics Command CENTCOM U.S. Central Command CEOI Communications-Electronics Operation Instructions CEP (1)Central East Pacific (MWARA) CEP (2)Circular Error Probability CEP (3)Circular Error Probable CEPPO Chemical Emergency Preparedness and Prevention Office CEPT Conference of Postal & Telecommunications Administrations (EU) CEPTAG Civil Emergency Planning Telecommunications Advisory Group (Joint US/Canadian) CERDEC Communications Electronics Research, Development and Engineering Center CERN Centre Europ'eene por la Recherche Nucleaire, Center for European Nuclear Research, huge particle accelerator center CERT (1)Community Emergency Response Teams (FEMA) CERT (2)Computer Emergency Response Team (Internet security) CERT (3)Computer Emergency Readiness Team (US Government) CF (1)Canadian forces CF (2)Center frequency CFAP Commandement Force Aerienne de Projection (French AF) CFARS Canadian Forces Affiliate Radio System CFB Canadian Forces Base CFBL Call Forwarding Busing Line (telco) CFBS Canadian Forces Broadcasting Service CFDA Call Forwarding Don't Answer (telco) CFEP Communications front end processor CFL Confidential Frequency List (good shortwave publication) CFM Cubic feet per minute CFR Code of Federal Regulations CFR 33 USCG Navigation Regulations CFR 46 USCG Vessel Regulations CFR 47 FCC Regulations CFS (1)Center for Standards CFS (2)Canadian Forces Station CFT Center Frequency Tone CG (1)Coast Guard CG (2)Commanding General CG cloud-ground lightning CGAS Coast Guard Air Station CG-C2 Coast Guard Command & Control CGCWOA (US) Coast Guard CW Operators Assn. (see CW) CGDN Coast Guard Data Net CGM (1)Computer Graphics Metafile CGM (2)Corrected Geomagnetic coordinates CGMS Coordinating Group for Meteorological Satellites CGSIC Civil GPS Service Interface Committee CGU Canadian Geophysical Union CGVTS Coast Guard Vessel Traffic System Ch Channel Ch mkr Channel marker CHAP Challenge Handshake Authentication Protocol (PPP) CHATH Chemically/Biologically Hardened Air Transportable Hospital CHBDL Common High Bandwidth Data Link CHBDL-ST Common High Bandwidth Data Link-Surface Terminal C-HFET Complementary Heterostructure Field Effect Transistor CHI cloud-height indicator CHINO sky condition at secondary location not available CHOP (1)Change in Operational Control CHOP (2)Chief Operator (Navy MARS) CHOP (3)Counter Measures Hands-on Program CHS Combat health support CHS Cylinder, Head, Sector (direct disk addressing) CIA Central Intelligence Agency (US) CIBAR Conference of International Broadcasters' Audience Research Services CIC (1) Combat Information Center (Navy) CIC (2) Combined Intelligence Center (US Air Force) CIC (3)Combined Intelligence Center CICA Competition in Contracting Act CICBMs Conventionally-armed ICBMs CICS Customer Information Control System (IBM) CID (1)Circuit Identifier CID (2)Combat Identification CIDE Communication Information Data Exchange CIDR Classless Inter-Domain Routing (Internet, replaces class A-C) CIDX Canadian International DX Club CIG ceiling CIIP Common Imagery Interoperability Profiles CIJ Close In Jamming CIL Command Image Library CINC Commander In Chief, replaced by CDR 2003 CINCLANT C in C, Atlantic, obsolete CINCNORAD C in C, NORAD, obsolete CINCPAC C in C, Pacific, obsolete CINCSTRAT C in C, Stratcom, obsolete CIOL Common Interface Objects Language CIPO Commanders in chief Interoperability Program Office CIPSO Common Internet Protocol Security Options CIRAF French acronym for international broadcast zone system CIRC Cross Interleaved Reed Solomon Code CIRF Co-Channel Interference Reduction Factor CIS (1)Combat Intelligence System CIS (2)Commonwealth of Independent States (replaced USSR) CISC Complex Instruction Set Computing CISCO Consolidated intelligence support to combat operations CISPR International Special Committee on Radio Interference CIT California Institute of Technology (CalTech) CITS Combat Information Transfer System CI-V Radio computer interface made by Icom CIW Combined Intelligence Watch CIWS Close-In Weapons System CJCS Chairman, Joint Chiefs of Staff (US) CJCSI Chairman of the Joint Chiefs of Staff Instruction CJCSM Chairman of the Joint Chiefs of Staff Memo CJFET Complementary junction field effect transistor CJMAO Central Joint Mortuary Affairs Office CK Check (usually word count in a message) CL (1)Centerline Lighting System CL (2)CW prosign: I am closing my station (clearing) Class A (1)Stage is biased to conduct continuously Class A (2)High explosive (military phone patches) Class B Stage is biased to conduct on half of cycle Class C (1)Stage is biased to conduct less than half Class C (2)Gunpowder (military phone patches) Class D Digital switching Class E New, like D CLC Circuit Link Control CLEW Common Link Eleven Waveform (NATO) Clg Calling CLIPER CLImatology and PERsistence (weather model) CLOVER Robust RTTY mode for HF CLR (1)Clear CLR (2)Clear below 12,000 feet (automated METAR) CLR (3)Common Language Runtime (MickeySoft) CLR (4)Combat Logistics Regiment CM (1)Countermeasures CM (2)Cipher Machine CM (3)Corrected Geomagnetic coordinates CM (4)Chemical Mace, a tear gas CM (5)Configuration Management cm (1)Centimeter cm (2)Control monitor CMARS Cruise Missile Autonomous Routing System CMAS Cheyenne Mountain Air Station, was CMAFB, CMAFS CMAWS Common Missile Approach Warning System CMC (1)Cheyenne Mountain Complex (NORAD) CMC (2)Command Management Center CMC (3)COMSAT Mobile Corporation, part of COMSAT CMCS COMINT Mission Collection System CMD (1)Command CMD (2)Network Command (ALE) CMDR Commander CMDS Countermeasure Dispenser Set CME Coronal Mass Ejection, causes aurora CMF Combat Mission Folder CMI Computer-managed instruction CMIS (1)Cheyenne Mountain Interface Subsystem CMIS (2)Closed Loop Maintenance Information System CMLSA Commercial Microwave Landing System Avionics CMMB China Multimedia Mobile Broadcasting CMO (1)Central Measurement and Signature Intelligence (MASINT) Office CMO (2)Civil-military operations CMOC Cheyenne Mountain Operations Center CMOS (1)Complementary Metallic Oxide Semiconductor CMOS (2)Cargo Movement Operations System CMP Common Management Practices CMR Crisis Management Reconnaissance CMRS Commercial Mobile Radio Service CMS (1)Canadian Maritime Service CMS (2)Calendar Messaging Service (Solaris) CMS (3)Common Mapping System CMS (4)Community Management Staff CMS (5)Counter Measures Set CMS (6)Counter Measures System CMSA Cruise Missile Support Activity CMT Cellular Mobile Telephone CMU Cheyenne Mountain Upgrade CMX Crisis Management Exercise (NATO) CMY Cyan, Magenta, Yellow (subtractive color printing) CMYK Cyan, Magenta, Yellow, blacK (4-color printing) CN (1)Communications network CN (2)Counter-narcotics CNA Center for Naval Analysis CNAAS Counter-narcotics air analysis system CNCE Communications nodal control element CNCS Centralized Net Control Station (Scope Command hub at Andrews AFB) CNE (1)Communications Network Environment CNE (2)Communications Node Emulator CNE (3)Certified Netware Engineer (Novell) CNES Centre National d'Etudes Spatiales (French space agency) CNI Communications, Navigation, and ID CNM (1)Communications Network management CNMI Commonwealth of the Northern Mariana Islands CNN Cable News Network CNO (1)Chief of Naval Operations CNO (2)Casualty notification officer CNR Combat Net Radio CNRADL Canadian RADIL (ROCC/AWACS digital information link) CNS (1)Communications, navigation & surveillance CNS (2)Central nervous system CNS (3)Consolidated NOTAM System (Another nested acronym courtesy FAA) CNTRA Chief of Naval Air Training (pronounced "Sinatra" like the singer) CO (1)Commanding Officer CO (2)Central Office (telcom) CO (3)Contracting Officer co UK version of .com (Internet domain) CO/MIS Commander, Management Information Center COA Courses of Action Coax Coaxial cable COBOL Common Business Oriented Language (clunky old programming code) COBRA (1)Coastal Battlefield Reconnaissance System COBRA (2)Counter Battery Radar COBRA (3)Coaxial Beam Rotating Antenna COBRA DANE US military air surveillance radar system COCOM Combatant command COD (1)Carrier Onboard Delivery COD (2)Collect On Delivery CODAR Coastal Ocean Dynamics Radar CoDE Coherent Digital Exciter Codec Coder/Decoder COE (1)Circle of Error COE (2)Common Operating Environment COE (3)Central Office Equipment COFAS Commandement Force Aerienne Strategique (French AF) COFC Container On Flat Car (as opposed to container car) COFF Common Object File Format (Windoze) CofS Chief of Staff COG Continuity Of Government (emergency plan) COI Critical Operational Issue COIL Chemical Oxygen-Iodine Laser COL Colonel COM (1)Computer file extension: load as simple command program COM (2)Commercial domain (Internet) COM (3)Component Object Module (Windoze) COMACC Commander, Air Combat Command COMAFFOR Commander Air Force Forces COMAFSPACE Commander, Air Force Space Command COMARSPACE Commander, U.S. Army Space Command COMASWFORLANT Commander, ASW Forces Atlantic COMCON Communications Condition (MARS) COMFAIRMED Commander, Fleet Air Mediterranean COMFAIRWINGTEN Commander, Fleet Airwing Ten COMHSWINGONE Commander, Helicopter Antisubmarine Wing One COMINT Communications Intelligence COMJAM Communications jamming Comm Communications (also "commo") COMM Communications COMMCOM Communications Command (USCG, replaces CAMS) COMMDET Communications Detachment (USCG) COMMSTA Communication Station COMMZ Communications zone COMNAVCOMTELCOM Commander, Naval Computer and Telecommunications Command COMOPTEVFOR Commander, Operational Test and Evaluation Force COMPATWING Commander, Patrol Wing COMPATWINGSLANT Commander, Patrol Wings Atlantic COMPTUEX Composite Training Unit Exercise (USN) COMPUINT Computer intelligence Compul Compulsory COMPUSEC Computer Security COMSAT (1)COMmunication SATellite COMSAT (2)Comsat Corp., US consortium & INMARSAT Convention rep COMSEABASED Commander, Sea-Based ASW Wings, Atlantic COMSEC Communication Security COMSTAT Communications Status Report COMSUBLANT Commander, Submarine Forces, Atlantic (USN) COMSUBPAC Commander, Submarine Forces, Pacific (USN) COMTAC Communications Tactical CONCISE Cosine Network's Central Information Service for Europe CONDX CW brevity: propagation conditions (usually wretched) CONELRAD Control of Electromagnetic Radiation, obsolete Config Configuration, configure conmara Italian Consulate, Maracaibo, Venezuela conmars Italian Consulate, Marseille, France conmopr Italian Consulate, possibly Montpellier, France conmpla Italian Consulate, Mar del Plata, Argentina CONOP(s) Concept of Operations(s) CONS continuous conspie Italian Consulate, possibly St. Pierre contolo Italian Consulate, Toulouse, France CONUS continental United States conwett Italian Consulate, Wettingen, Switzerland COOP Continuity Of Operations (US Army) COP Common Operational Picture Coq Coquelet (French teleprinting system, after "Rooster") Coq8 8-bit Coquelet COR (1)Carrier operated relay COR (2)Consolidated Operations Room ("Lights Out") COR (3)Correction to a previously disseminated weather report CORES Commission Registration System (FCC) COS Communication Operations Segment COSCOM Corps support command COSE Common Open Software Environment COSIP Computer Open System Interface Processor COSPAS Acronym for Russian SARSAT COT Changeover time COTHEN Cellular Over The Horizon Enforcement Network (US) COTS Commercial Off-The-Shelf COWS Cells On Wheels (post-disaster cellphone service) CP (1)Command Post CP (2)CW general call: "Hello -- [2 or more callsigns follow]" CP (3)Contental Polar (air mass) CP/M Early Z80 operating system, might or might not have stood for "Control Program for Microcomputers," or "Control Program/Monitor." The guy who would know is dead, having narrowly missed out on being richer than Bill Gates. CPA (1)Closest Point of Approach CPA (2)Certified Public Accountant CPAS Cellular Priority Access Service CPCA Camp Parks Communications Annex (USAF) CPDL Controller-Pilot Data Link CPDLC Controller-Pilot Data Link Communications CPE Customer Premise Equipment (telco) CPFSK Continuous-Phase Frequency Shift Keying CPM Continuous Phase Modulation CPO Chief Petty Officer CPR Cardio-pulmonary resuscitation CPS (1)Characters Per Second CPS (2)Cellular Priority Services (US NCS) cps Cycle per second (one Hertz) CPT Captain (US Army) CPU Central Processing Unit (computer h/w) CPX Command Post Exercise (NATO) CQ General call: "Hello all stations" CQD "Hello All Stations, Distress," no longer used CQWW CQ World Wide (Amateur DX contest) CR Carriage Return CRAF Civil Reserve Air Fleet CRATT Crypto Radio Teletype (usually military & encrypted) CRC (1)Cyclic Redundancy Check (computer error test) CRC (2)CONUS Replacement Center CRC (3)Control & Reporting Center CRE Control & Reporting Element CREW Counter RCIED Electronic Warfare (Nested Acronym) CREN Corporation for Research and Educational Networking CRIS Communications Resource Information Sharing (US NCS) CRM Computer Resource Management CRO (1)Cathode-Ray Oscilloscope CRO (2)Croatia (country code) CRO (3)Coaxial Resonator Oscillator CROSS Centres Regionaux Opérationnels de Surveillance et de Sauvetage (French RCC, see RCC) CROWD36 Russian diplomatic MFSK mode CRPLF French language: Francophonic Public Radio Community CRR Carrier CRRL Canadian Radio Relay League CRS Coastal Radio Station CRT Cathode-Ray Tube (usually a computer terminal) CRTC Combat Readiness Training Center CS (1)combat support CS (2)communication squadron CS (3)Chicken S-it CS (4)Chemical Shield (a tear gas) CS&C Office of Cybersecurity and Communications (DHS) CSAF Air Force Chief of Staff CSAR Combat Search and Rescue CSARP Common SAR Processor CSB Corps support battalion CSC (1)Combat Support Center (AFOC) CSC (2)Combat stress control CSC (3)Computer Software Component CSCI Computer Software Configuration Item CSE Client/Server Environment CSEL Combat Survivor Evader Locator (pilot survival radio) CSG (1)Carrier Strike Group CSG (2)Corps support group CSH Combat support hospital csh C-shell, popular Unix command interpreter CSMA/CD Carrier Sense Multiple Access/ Collision Detection CSOM Computer Software Operators Manual CSP Communications Support Processor C-SPAN Cable-Satellite Public Affairs Network (US) CSQ Carrier SQuelch CSS (1)Combat service support CSS (2)Central Security Service (US SIGINT, run by NSA director) CSS (3)Cascading Style Sheets CSS (4)Content Scrambling System (DVD encryption) CSSCS Combat Service Support Control System CST (1)Central (US) Standard Time CST (2)Caribbean Support Tender CST (3)Civil Support Team CSTARS COMBAT SENT Technical Acquisition Receiver System CSU Computer Software Unit CT (1)Center Tap CT (2)("Charlie Tango") - Communications Technician (on an aircraft) CTA Control Area CTAF Common Traffic Advisory Frequency CTAPS Contingency Tactical Air Combat System CTBT Comprehensive Test Ban Treaty CTC (1)Centralized Traffic Control (railroad) CTC (2)Counter-Terrorism Command CTCSS Continuous Tone Coded Squelch System ("PL") CTI Computer - Telephone Integration CTIA Cellular Telecommunications Industry Assn CTLZ Control Zone CTP Critical Technical Parameter CTR Combat Training Range Ctrl (1)Control Ctrl (2)Computer's control key, sometimes shown with a ^ CTS Clear To Send (Serial I/O handshaking line) CTT Commander's Tactical Terminal CU CW brevity code: "See you" CUAGN CW brevity code: "See you again" CUBIC Common User Baseline for the Intel Community CUCV commercial utility cargo vehicle CUL CW brevity code: "See you later" CUSEC Central U.S. Earthquake Consortium (HF net) CV (1)USN Aircraft Carrier CV (2)Vice Commander CVBG Carrier Battle Group CVIC Carrier Intelligence Center CVN US nuclear aircraft carrier CW (1)Continuous Wave (usually Morse code) CW (2)Clockwise (rotation) CW (3)Composite Wing CWDE Chemical Warfare Defense Ensemble CWIS Campus-Wide Information System CWISP Campus-Wide Information System Protocol CWOC Composite Wing Operations Center CWP Central West Pacific (MWARA) CWS Combat Weather System CWSS COP Web Services System Cygnus Cygnus, Your Gnu Support (nested recursion; see Gnu) CZ (Panama) Canal Zone D (1)Down D (2)Diode D/A Digital/Analog converter D/L (1)Downlink D/L (2)Download D2 Degrade and Destroy D2C D-2 Small Cassette D3 Degrade Disrupt Deny D4 (1)Degrade Disrupt Deny Destroy D4 (2)Deny, Disrupt, Degrade, & Destroy D4EN Disrupt, Delay, Destroy, Exploit, or Neutralize DA (1)Directional antenna DA (2)Department of the Army DA-2 Station changes directional pattern at night (FCC) DAB Digital Audio Broadcasting DAB+ Newer DAB standards, not backward compatible DAC (1)Digital-to-Analog Converter DAC (2)Disaster Assistance Center (FEMA) DAC (3)Disaster Application Center DACN Department and Agency Continuity Network (FEMA) DACT Data Automated Control Terminal DAE Disaster Assistance Employee DAGS Data Architecture and Gateway Services dah Morse code dash [~] DAMA Demand Assigned Multiple Access (UHF SATCOM) D-AMPS Digital Advanced Mobile Phone System DAMSON Doppler And Multipath Sounding Network DAQCS (1)Distress Alert Quality Control System DAQCS (2)Data Acquisition and Quality Control System DARN (1)Dual Auroral Radar Network DARN (2)Disaster Amateur Radio Network, SoCal 440 MHz system DARO Defense Airborne Reconnaissance Office DARP Defense Airborne Reconnaissance Program DARPA Defense Advanced Research Projects Agency DARS Digital Audio Radio Service (US) DARTS Dynamic Avionics Real-Time Scheduling DAS (1)Data Aquisition System DAS (2)Distributed Antenna System DASR Digital Airport Surveillance Radar DAT Digital audio tape D-ATIS (1)Digital Automated Terminal Information Service D-ATIS (2)Digital Air Traffic Information Service (FAA) DAWS Defense Automated Warning System DB (1)Directional Beacon DB (2)Dead body dB Decibel (1/10 Bel, a logarithmic voltage or power ratio) dBA Sound level (corrected to "A" scale dB) dBc Decibels referenced to full-rated peak envelope power DBCS Double byte character set dBd Decibel gain over dipole antenna dBi Decibel gain over (theoretical) isotropic antenna dBic Db gain over circular isotropic DBM (1)Doubly balanced mixer DBM (2)Data Block Message dBm Decibels over 1 mW into 50 ohms, usually rf, 0 dBm = 0.316 Vp DBMS Data Base Management System DBPSK Differential Binary Phase-Shift Keying DBS Direct broadcasting satellite (system) dBW Db over one watt DC Direct Current DC1 Device Control 1 (ASCII flow control) DC2 Device Control 2 (ASCII) DC3 Device Control 3 (ASCII flow control) DC4 Device Control 4 (ASCII) DCA (1)Defense Communications Agency (now DISA) DCA (2)Defensive counter Air DCA (3)Dual-Capable Aircraft DCAC Defense Communications Agency Circular (now DISA) DCCP Datagram Congestion Control Protocol DCD Data Carrier Detect (packet modems) DCDR Deputy Commander DCE (1)Data Communication Equipment (like a modem) DCE (2)Distributed Computing Environment DCG Deputy commanding general DCI (1)Defensive Counter Information DCI (2)Director of Central Intelligence DCID Director of Central Intelligence Directive DCO Defense Coordinating Officer DCOM Distributed Component Object Model (Windoze) DCP (1)Data Collection Platform DCP (2)Defense Cryptologic Program DCPA Defense Civil Preparedness Agency, now FEMA DCR Direct Conversion Receiver ("Homodyne") DCS (1)Defense Communications System DCS (2)Disaster Communications System, amateur, from RACES DCS (3)Digital Coded Squelch DCS (4)Distributed Control Systems DCT (1)Digital Communications Terminal DCT (2)Direct Cosine Transform DCTN Defense Commercial Telecommunications Network DCW Digital Chart of the World DD (1)Dual Diversity DD (2)Digital Data DDD Maritime preamble for relayed distress message DDDS Defense Data Dictionary System DDM DoD Data Model DDN Defense Data Network DDNS Dynamic Domain Naming System/Server (Internet) DDO Dynamic Drive Overlay (used by Disk Manager on the PC) DDOS Distributed Denial Of Service (attack) DDPO Defense Dissemination Program Office DDR (1)Dual Diversity Receiver DDR (2)Double Data Rate (memory) DDR (3)Deutsche Demokratische Republik (1949-1990) DDRR Direct Driven Ring Radiator (antenna) DDRS Defense Data Repository System DDS (1)Direct Digital Synthesis DDS (2)Defense Dissemination System DDT (1)Delay/Denial Technology DDT (2)Dynamic Debugging Tool, named for old pesticide DE Morse code prosign meaning "from" DEA Drug Enforcement Administration (US) DEC Digital Equipment Corporation, made some nice computers DECCA Low-frequency CW phase comparison navigation (company name) DECM Deceptive Electronic Countermeasures DECnet DEC's name for networking protocols and products DECT Digital European Cordless Telecommunications DEFCON DEFense CONdition, 1-5; 5 is peace, 1 is global thermonuclear war (STRATCOM) DEMIZ DEW East Military Identification Zone DEPCON Departure Control DE-QPSK Differentially Encoded Quaternary Phase Shift Keying DES Data Encryption Standard DES-FED Stronger (108 bit) DES used by US government Det Detector DEW Distant Early Warning (old radar in Canada) DF (1)Direction finding DF (2)Direction finder ("duffer") DF (3)Damping Factor DFAD Digital Feature Analysis Data DFAS Defense Finance and Accounting Service DFCC Digital Flight Control Computer DFCS Digital Flight Control System DFCW Dual-Frequency Continuous Wave DFO Disaster Field Office DFRC Dryden Flight Research Center (NASA) DGI Dirección General de Inteligencia, old name for Cuban DI DGM Digital group multiplexer DGPS-MSK Differential GPS, Minimum Shift Keying DGPS-QPSK DGPS-QPSK : Differential GPS, Quarternary Phase Shift DGS Deployable Ground Stations DHCP Dynamic Host Configuration Protocol DHFCS Defence High-Frequency Communications System (UK) DHS Department of Homeland Security DHTML Dynamic Hypertext Markup Language (web) DI Dirección de Inteligencia, main Cuban intelligence agcy DIA Defense Intelligence Agency DIAC Defense Intelligence Analysis Center DIAL Differential Absorption Lidar DIAM Defense Intelligence Agency Manual DICE Data Integration & Collection Environment DIDOP Digital Image Data Output Product (Differential GPS, QPSK DIG Domain Internet Groper DIGEST Digital Geographic Information Exchange Standard DIGI ~ Digipeater, simplex digital repeater DII Defense Information Infrastructure DIMM Double In-line Memory Module DIMMS Double In-line Modular Memory System DIN German standards agency DIOP Data Input/Output Port DIP Dual In-line Package (chips or small switches) Diplo Diplomatic traffic, usually encrypted DIPS Digital Image Processing System DIRCM Directed Infrared Countermeasures DIRMOBFOR Director of Mobility Forces DIS (1)Defense Investigative Service DIS (2)Distributed Interactive Simulation DIS (3)Distributed Interactive System DIS (4)Draft International Standard DIS (5)Daily Intelligence Summary DIS (6)Data and Information System DIS (7)Defense Information System DIS (8)Defense Intelligence Service DISA Defense Information Systems Agency DISAC Defense Information Systems Agency Circular DISC Packet control frame: Disconnect DISCO Defense Industri+al Security Clearance Office DISCOM Division support command DISN Defense Information Systems Network dit Morse code dot [~] DITAW Detect, Identify, Track, Assesment, & Warn DIW Dead in the water DIWSA Digital Imagery Workstation Suite Afloat DJ Deceptive Jamming DJBDNS Daniel J. Bernstein DNS (more secure than BIND) DL (1)Download DL (2)Data Link DL (3)Driver's License (police) DLA Defense Logistics Agency DLC Data Link Control DLE Data Link Escape (ASCII) DLL Dynamically Linked Library (computer programs) DLMM Depot Level Maintenance Manual DLQ Deck Landing Qualification DLRP Data Link Reference Point, a USN authenticator DM (1)Delay Modulation (Miller Coding) DM (2)Packet control frame: Disconnect Mode (busy) DMA (1)Direct Memory Access DMA (2)Defense Mapping Agency DMAAC Defense Mapping Agency Aerospace Center DMAHC Defense Mapping Agency Hydrographic Center DMAHTC DMA Hydrographic Topographic Center DMAL Defense Mapping Agency List DMAT Disaster Medical Assistance Team DMATC Defense Mapping Agency Topographic Center DMB (1)Data Marker Buoy DMB (2)Digital Multimedia Broadcasting (S-DMB=Satellite, T-DMB=terrestrial) DMB-T/H Digital Multimedia Broadcast-Terrestrial/Handheld (China) DMC Defence Management Committee (Canada) DMCA Digital Millennium Copyright Act DMD Digital Micromirror Device DME Distance Measuring Equipment (airport approach) DMI Depot Maintenance Interservicing DMR Digital Mobile Radio (standard) DMSO Defense Modeling and Simulation Office DMSP (1)Distributed Mail System Protocol DMSP (2)Defense Meteorological Satellite Program DMT Discrete Multi-Tone DMTD Digital Message Transfer Device DMTF Distributed Management Task Force DMUX Demultiplexer DMZ Demilitarized Zone (Korea) DN (1)Dutch (Royal) Navy DN (2)Directory Number (telco) DNC Digital Nautical Chart DNCC Deployed Network Control Center DND Department of National Defence (Canada) DNS Domain Naming System/Server (Internet) DNSSEC DNS Security DO design objective DOA Dead On Arrival DOB Date Of Birth (police) DOC (1)Department of Commerce (US) DOC (2)Department Of Communication (Canadian "FCC") DoD Department of Defense (US) DoDD Department of Defense Directive DoDIIS (1)Defense Intelligence Information System DoDIIS (2)DOD Intelligence Information System DODISS (3)Department of Defense Index of Specifications and Standards DoDISS (4)DoD Index of Specifications and Standards DoDSI Department of Defense Security Institute DoDSSP DoD Single Stock Point DOE Department Of Energy (US) DOI Department Of the Interior (US) DOJ Department Of Justice (US) DOMS Director Of Military Support (MARS) DOS (1)Department of State (US) DOS (2)Disk Operating System (generic) DOS (3)MS-DOS (proprietary PC op-sys) DOS (4)PC-DOS, IBM version of above, obsolete? DOS (5)Denial of Service (attack) DOT Department of Transportation (US) DOW Doppler On Wheels (storm-chasing radar equipment) DP Development Prototype DPCA Displaced Phase Center Antenna DPCM Differential Pulse Code Modulation DPDT Double-Pole, Double Throw DPG Defense Planning Guidance DPI (1)Dots Per Inch DPI (2)Deep Packet Inspection (surveillance) DPL Diode-Pumped Laser DPSK Differential Phase-Shift Keying DPST Double-Pole, Single-Throw dpx Duplex DQPSK Differential Quadrature Phase-Shift Keying DR low drifting DRAC Dynamic Relay Authorisation Control DRAM Dynamic Random Access Memory DRE Drug Recognition Expert DRFM Digital Radio Frequency Memory DRFMU Digital Radio Frequency Memory Unit DRM (1)Digital Radio Mondiale DRM (2)Digital Rights Management DRO Dielectric Resonator Oscillator DRS Deployable Red Switch DRSN Defense RED Switch Network DS (1)Direct support DS (2)Dust storm DSA Division support area DSA/SMC Deputy for Systems Acquisition/Systems Management Center DSB Double sideband DSC Digital Selective Calling (GMDSS) DSI Defensive Simulation Internet DSL Digital Subscriber Line DSLAM Digital Subscriber Line Access Multiplexer DSM (1)Digital Switching Module DSM (2)Distributed Shared Memory DSN (1)Defense Switched Network (old AUTOVON) DSN (2)Deep Space Network (NASA) DSNET Defense Secure Network DSNT distant DSOR Depot Source of Repair DSP Digital signal processing DSR Data Set Ready (Serial I/O primary handshaking line) DSRC Dedicated Short Range Communications DSS (1)Digital Satellite System DSS (2)Diplomatic Security Service Dst Disturbance Storm Time, equatorial magnetospheric activity index D-STAR Digital Smart Technology for Amateur Radio DSTO Defence Science & Technology Organisation (Australia) DSVD Digital Simultaneous Voice and Data DSVT Digital Subscriber Voice Terminal DSW Russian CW brevity code: "Daswedanya" (Goodbye) DT (1)District T (USCG) DTAC Division tactical command post DTC Design to Cost DTD Data Transfer Device DTE Data Terminal Equipment (computers, workstations, dumb terminals) DTED Digital Terrain Elevation Data DTG Date time group (example: ddhhmm mon yy z) DTIM Delivery Traffic Indication Message DTM (1)Data Text Message DTM (2)Data Transfer Module DTM (3)Digital Technology Model DTMB Digital Terrestrial Multimedia Broadcast (Chinese TV, nee DMB-T/H) DTMF Dual Tone Multi Frequency (like telco "touch tone") DTMF-RA Dual Tone Multi-Frequency - Remote Access DTO Division tactical operations center DTOP Digital Topographic Data DTR Data Terminal Ready (Serial I/O primary handshaking line) DTS (1)Digital Transmission System (Euro radio e-mail s/w) DTS (2)Data Terminal Set DTS (3)Digital Terrain System DTSS Digital Terrain Support System DTT Digital Terrestrial Television DTV Digital Television DU (1)widespread dust (weather) DU (2)depleted uranium DUATS Direct User Access Terminal System DUP-ARQ Hungarian diplomatic teleprinting system DUPE CW prosign: message or contact is a duplicate DUSD Deputy Undersecretary of Defense DUT1 UTC correction interval to get UT1 DV (1)Distinguished Visitor DV (2)Digital Voice DVA Department of Veterans Affairs DVB Digital Video Broadcast (Europe) DVB-C Digital Video Broadcast (cable) DVB-H Digital Video Broadcast (handheld) DVB-S Digital Video Broadcast (satellite) DVB-SH Digital Video Broadcast (satellite handheld) DVB-T Digital Video Broadcast (terrestrial) DVD Digital Versatile Disk DVFR Defense Visual Flight Rules DVI Digital Video Interface DVM Digital Voltmeter DVMT Dynamic Video Memory Technology DVP (1)Distinguished Visitor Protocol (US Air Force DVP (2)Digital Voice Protection (secure voice) DVSI Digital Voice Systems, Inc. DW Deutsche Welle DX (1)Distant Transmitter. The distance can be either geographic or psychological. DX (2)First transmission of FEC character DX (3)Duplex DXAC DX Advisory Committee (ARRL) DXCC Coveted amateur radio award, for confirming at least 100 countries DXing The hobby of listening to distant radio or television DZ (1)Drop zone DZ (2)drizzle DZST Drop Zone Support Team E (1)Electromotive force (in volts) E (2)east, ended E (3)E-region (middle zone of ionosphere) E (4)Electric field E2K Enigma 2000, numbers listening group EA (1)East Asia (MWARA) EA (2)Electronic Attack EAC Echelons above corps EAD Echelons above division EAF Expeditionary Airfields EALS Emergency Airfield Lighting System EAM Emergency Action Message EAP Extensible Authentication Protocol EAR End Air Refueling EARN European Academic and Research Network EAS (1)Emergency Alerting System, replaced EBS EAS (2)Equivalent Air Speed EAS (3)Electronic Article Surveillance EASA European Aviation Safety Agency EBB Electronic bulletin board EBC Emulated buffer computer EBCDIC Extended Binary Coded Decimal Interchange Code, old IBM EBIOS Enhanced Basic Input/Output System (PCs with disks over 540 meg) EBONE A pan-European Backbone service EBS Emergency Broadcasting System, replaced CONELRAD EBU European Broadcasting Union EC (1)Electronic Combat EC (2)Emergency Coordinator ECB Echelons corps and below ECC (1)Error Correction Code (better than parity) ECC (2)Error Checking & Correcting (memory chip) ECC (3)Error Control Coding ECCM Electronic Counter-Countermeasures ECCO Electronic Combat Coordination Officer ECDIS Electronic Chart Display and Information System ECDIS-N Electronic Chart Display and Information System-Navy ECHS Extended Cylinder, Head, Sector (addressing) ECM (1)Electronic countermeasures ECM (2)Electronic Cipher Machine ECMWF European Centre for Medium-Range Weather Forecasts ECN Explicit Congestion Notification ECOM Emergency Communications ECRS East Coast Radar System ECS Electronic Chart System ed Edit; any of several funky line editors for old printing TTYs connected to computers EDC Error Detection Code EDD Electronic Document Delivery EDFMCM Environmental Data Fusion for Mine Countermeasures EDGE Enhanced Data Rates for Global Evolution (telephony) EDI Electronic Document Interchange EDO Extended Data Output (memory chip) EDP Electronic Data Processing EDPT Enhanced (fixed) Disk Parameter Table EDR Enhanced Data Rate EDS Explosives Detection Systems EDSAC Electronic Delay Storage Automatic Calculator (1949) EDT Eastern (US) Daylight Time EDTV Enhanced Definition Television edu Educational Institution domain (Internet) EDVAC Electronic Discrete Variable Computer (1945) EE (1) Transmission is in English EE (2) Person with Electrical Engineering degree EEA European Economic Area EEC European Economic Community EECEN Electronics Engineering Center, NJ (USCG) EEFI Essential Elements of Friendly Information (COMSEC) EEFI 1 Position (notification prepended by ZNX) EEFI 2 Capabilities EEFI 3 Operations EEFI 4 Electronic Warfare EEFI 5 Personnel EEFI 6 COMSEC breach EEFI 7 Wrong circuit used EEFI 8-10 Spare EEI Essential Elements of Information (Federal report form) EEJ Equatorial Electrojet, might cause trans-eq spread-f propagation EEPROM Electronically Erasable Programmable Read Only Memory EEZ Exclusive Economic Zone ("200-mile limit") EFAS Enroute Flight Advisory Service EFF Electronic Frontier Foundation, Internet free speech group EFFI Essential Elements of Friendly Information EFTO Encrypted for transmission only EGC Enhanced Group Call (GMDSS) EGNOS European Geostationary Navigation Overlay Service EGP Exterior Gateway Protocols EGPRS Enhanced General Packet Radio Service EGS European Geophysical Society E-HA Enroute High Altitude EHS External Hostile Structured threat EHU External Hostile Unstructured threat EI-232 Latest name for RS-232, the serial interface standard EIA (1)Electronic Industries Association, replaced RETMA EIA (2)Equatorial Ionization Anomaly EICC Emergency Information and Coordination Center (FEMA) EIDE Enhanced Integrated Drive Electronics, ATA version once proprietary to WD EIG External Interface Gateways EINE EINE Is Not Emacs (recursive acronym; see Emacs) EIP ELINT Improvement Program EIRP Equivalent Isotropically Radiated Power EIS Enhanced Imaging System EISA Extended Industry Standard Architecture EISCAT European Incoherent Scatter Radar (research) E-LA Enroute Low Altitude ELF (1) Extremely Low Frequency (30-300 Hz) ELF (2) US military comm system using same ("Project Elf") ELINT Electronic Intelligence elm ELectronic Mailer (Unix) ELSEC Electronic Security ELT Emergency Locator Transmitter ELV Expendable Launch Vehicle EM (1)Electromagnetic EM (2)Extended mission EM (3)Emergency management EM (4)End of Medium (ASCII) Emacs Editing Macros, powerful if ungainly, Unix text editor E-mail Electronic mail, usually by computer EMC Electromagnetic compatibility EMCON (1)Electromagnetic Radiation Control EMCON (2)Emission Control (radio, etc, not smog) EMCS ELINT Mission Control System EME (1)Electromagnetic energy EME (2)Earth-Moon-Earth (VHF/UHF "moonbounce") EMF Electromotive force (back-EMF occurs in coils & motors) EMI Electromagnetic incompatibility EMMAC European Multimedia Associations Convention EMP Electromagnetic pulse EMS (1)Extended Memory Specification (IBM PC, old LIM spec) EMS (2)Emergency Medical Services EMSEC Emanations Security EMT Emergency Medical Technician, public safety certificate EMWIN Emergency Manager's Weather Information Network ENC Electronic Navigational Chart ENE East-northeast ENF ELINT Notation File engr engineer ENIAC Electronic Numerical Integrator And Computer, 1940s vacuum tube calculating machine ENIGMA (1) European Numbers Information Gathering & Monitoring Assn ENIGMA (2)[~]Historic German crypto machine, WW II code broken by Allies ENJEP Euro-Nato Jet Pilot Training (at Sheppard AFB) ENQ (1)Enquiry, sent by computer to get ACK/NAK response (ASCII 05) ENQ (2)Enquiry (Like Who Are You?) ENS External Non-Hostile Structured threat ENTNAC Entrance National Agency Check ENU External Non-Hostile Unstructured threat EO Electro-Optical EO/IR Electro-Optical/Infrared EOB Electronic Order of Battle EOC Emergency Operations Center EOD Explosive Ordnance Disposal, the bomb squad EOL End of (design) life EO-LOROPS Electro-Optical Long Range Oblique Photography System EOP Emergency Operations Plan EOS Earth Observing System EOT (1)End Of Transmission EOT (2)End Of Tape EOW End Of Watch EP Electronic Protection EPA Environmental Protection Agency EPIC El Paso Intelligence Center (US Customs) EPIRB Emergency Position Indicating Radio Beacon EPL ELINT Parameter List EPLRS Enhanced Position Location Reporting System EPROM Electrically Programmable Read-Only Memory EPS (1)Emergency Planning Subcommittee EPS (2)Enhanced Processing Segment EPS (3)GOES Energetic Particle Sensor, measures solar flares EPU Emergency Power Unit EPW Enemy prisoner of war ER (1)Eastern Range ER (2)Emergency room ERASER Enhanced Recognition & Sensing Radar ERFAK Emergency Response Fly-Away Kit (US Govt) ERLink Emergency Response Link (US Govt) ERMA Electronic Recording Machine Accounting (1959, first check reader) ERMES European Radio MEssage System erp Effective radiated power ERPS External Frequency Interference Protection System ERT Emergency Response Team (FEMA) ERT-A Advance Element of the Emergency Response Team (FEMA) ERTS Earth Rotation Time Service, keeps track of planet's actual position in space ES (1)Electronic Support ES (2)CW brevity code: "And" ES (3)Sporadic E propagation, or clouds making same ES (4)Extended Squitter ESA European Space Agency ESC (1)Enhanced Satellite Capability (US NCS) ESC (2)Escape (computer character) ESE East-southeast ESF Emergency Support Function (part of NTSP; 1-12) ESM Electronic Support Measures ESMC Eastern Space & Missile Center ESMTP Extended Simple Mail Transfer Protocol (does this mean it's no longer simple?) ESN Electronic Serial Number ESS (1)Electronic Switching System (landlines) ESS (2)Electronic Scoring Site ESSID Enhanced Service Set Identifier (wi-fi) EST (1)Eastern (US) Standard Time EST (2)Emergency Support Team (FEMA) ET (1)Extra-terrestrial ET (2)External Tank (NASA) ET (3)Eastern Time (US) ETA Estimated time of arrival ETB End of Transmission Block ETD (1)Estimated time of departure ETD (2)End-of-Train Device ETD (3)Explosives Trace Detection ETLA Extended Three-Letter Acronym (a four-letter acronym) ETOH Alcohol (for some reason, paramedics say the chemical name) ETRAC Enhanced Tactical Radar Correlator ETSI European Telecommunications Standards Institute ETX End Of Text (ASCII) EUCOM European Command Eunet European part of UUCP, Unix file transfer network EUR Europe (MWARA) EUV Extreme ultraviolet (can ionize) EVS Electro-Optical Viewing System EW Electronic warfare EWIR Electronic Warfare Integrated Reprogramming EWMS Electronic Warfare Management System EWN Evangelical World Network, operates WEWN EWO (1)Electronic Warfare Officer (backseater) EWO (2)Emergency War Order EWPE EW Processing Element EWR Early Warning Radar EWS Early Warning System EXE Computer file extension: loads as executable EXE2BIN PC program for creating .COM files from .EXE f Frequency (in Hertz) F (1)Farad (a huge capacitor; usually uf or pf) F (2)F-region, highest zone of ionosphere F/B Front to back ratio (antennas) F/O (1)Fiber optics F/O (2)Follow-on F/V Fishing Vessel F/W Fixed wing (airplane) F0 FM carrier, no modulation, sounds just like A0, now N0N F1 (1)In daytime, lower layer of F region F1 (2)Frequency number one (F2, F3...) F1B Mode designator: frequency shift keying F2 In daytime, upper layer of F region F2B Mode designator: Audio frequency-shift keying F3C Mode designator: fax F3E Mode designator: FM voice or broadcasting FAA (1)Federal Aviation Administration (US) FAA (2)Foreign Assistance Act FAAA General call: "All French warships" [~] FAADC3 Forward Area Air Defense Command, Control, Communications Intelligence System (US Army) FAC (1)Field-Aligned Current, an irregular propagation mode FAC (2)Forward Air Controller FACSFAC Fleet Area Control & Surveillance Facility (US Navy) FADEC Full Authority Digital Engine Control FAE Fuel Air Explosive FAF (1)Fast Access Format FAF (2)French Air Force FAGDS Federation of Astronomical and Geophysical Data Services FAI Field-Aligned Irregularities, like FAC FAM Federal Air Marshal FANS Future Air Navigation System (FANS-1, FANS-A, FANS-1/A, FANS-B+) FAPSI Federal Agcy for Govt Comm & Info (Russian, replaced KGB, now also replaced) FAQ Frequently Asked Questions (Internet/USENET) FAR Federal Aviation Regulations FARP Forward Arming & Refueling Point FAS (1)Frequency Assignment Subcommittee (of IRAC) FAS (2)Federation of American Scientists FASC Forward area signal center FAST (1)Field Assessment Team (FEMA) FAST (2)Fleet Antiterrorist Strike Team (US Marines) FAST (3)Fast Auroral Snapshot Small Explorer satellite (NASA) FAST Field Adaptable Systems Technology FAT (1)File Allocation Table (MS-DOS) FAT (2)First Article Test FAT32 32-bit File Allocation Table (Newer MS-Windows) FAX Facsimile FB CW brevity code: "Fine Business" (really good) FBI Federal Bureau of Investigation (US) FBIS Foreign Broadcast Intelligence Service (WWII) FBO Fixed Base Operator FC funnel cloud FCC Federal Communications Commission FCMP Fleet Composite Broadcast (USCG Honolulu) FCO Federal Coordinating Officer (FEMA) FCS Frame Check Sequence (wi-fi) FD (1)Floppy Disk FD (2)Fixed Disk (confusing!) FDD Floppy Disk Drive FDDI Fibre Data Distribution Interface FDK Frequency-Difference Keying FDM Frequency-Division Multiplex FDMA Frequency Division Multiple Access FDPT Fixed Disk Parameter Table FDX Full Duplex FEBA Far East Broadcasting Assn FEC Forward error correction teleprinter system FEC-A One-way traffic FEC teleprinter system FECC Federal Emergency Communications Coordinator FECTOR Teleprinting over radio, mode B FED-STD Federal Telecommunication Standard FEK Frequency Exchange Keying FEMA Federal Emergency Management Agency FEP (1)Front End Processor (computers) FEP (2)FLTSAT EHF Package (Navy) FET Field-effect transistor FEW Few clouds FF (1)French Forces FF (2)Transmission is in French FF (3)Formfeed (ASCII) FFH (1)Fast Frigate Helicopter FFH (2)Fast Frequency Hopping (spread spectrum scheme) FFHT-net Fast-Frequency-Hopping Training net FFRDC Federally Funded Research& Development Center (MITRE Corp.) FFT Fast Fourier transform FG (1)Foreign Government (Foxtrot Golf) FG (2)Fog FGS Federal German Ship FH Field hospital FHWA Federal Highway Administration (US) FI Field Investigation, Field Interview (police) FIA (1)Fibreoptic Industry Association (UK) FIA (2)Federation Internationale d'Automobile (Formula 1 racing) FIBI filed but impracticable to transmit FIFO First in, first out FIGS Figures case (Baudot upper case) figs figures follow FIM Flight Information Manual FINDS Flexible Information Dissemination System FIPS Federal Information Processing Standards FIR (1)Flight Information Region FIR (2)Finite Impulse Response FIRESCOPE Firefighting Resources of Southern California Organized for Potential Emergencies FIRRS FAAR/Iceland Air Defense Remote Rekeying System FIRST (1)Forum of Incident Response and Security Teams (computers) FIRST (2)first observation after a break in coverage at manual station FIS Flight Information Services FIS-B Flight Information Services-Broadcast FISIN Foreign Instrument Signals Intelligence FISINT Foreign Instrumentation Intelligence FIST Fleet Imagery Support Terminal (US Navy) FISTA Flying Infrared Signatures Technology Aircraft FITFEEL Fast Information Transfer For Extremely Errored Links FL (1)Flight level FL (2)Focal Length FLAK German: FLeigerAbwehrKannonen (anti-aircraft artillery) FLASER Forward Looking Infrared Laser Radar FLIP Flight Information Publication (US DoD) FLIR Forward looking infrared Flops Floating point operations per second FLOT Forward Line of Own Troops FLOTUS First Lady Of The United States (President's wife) FLR Forward looking radar Flt (1)flight Flt (2)fleet (US Navy) FLT HICOM Fleet High Command (US Navy) FLTSAT Fleet Satellite, Navy comsat FLTSATCOM Fleet Satellite Communications (US Navy) FM (1)Frequency Modulation FM (2)Field manual FM (3)("Foxtrot Mike") VHF FM (US Navy) FM (4)CW brevity: From [~] FM (5)Field Meteorological FM (6)Frequency Management FMA-net Frequency Management A-net FMC (1)Field Maintenance Center FMC (2)Force Mobile Command FMC (3)Flight Management Computer FMCW Frequency-Modulated Continuous Wave FMH Federal Meteorological Handbook FMH-1 Federal Meteorological Handbook-1 FMH-2 Federal Meteorological Handbook No.2 FMO Frequency Management Office FMOP Frequency Modulation On Pulse FMOW FM Orderwire (US military) FMP Fleet Modernization Program FMS (1)Flight Management System FMS (2)Foreign Military Sales FMT-net Frequency Management Training net FN French Navy FNARS FEMA National Radio System (nested acronym!) FNG Friendly new guy/gal (possible security risk) FNPRM Further Notice of Proposed Rule Making (FCC) FOB (1)Field Operations Bureau (FCC) FOB (2)Freight On Board (shipping regs) FOB (3)"Fresh Off the Boat" (humorous) FOD Foreign Object Damage FOG Field Operations Guide FOIA Freedom of Information Act FOLDOC Free Online Dictionary Of Computing FORSCOM Forces Command FORTRAN Formula Translator (early IBM computer language) FOSIC Fleet Ocean Surveillance & Information Center FOT Optimum Traffic Frequency (fq that will work most days of period) FOUO For Official Use Only FOV Field of View Foxes THE QUICK BROWN FOX... test [~] FPLMTS Future Public Land Mobile Telecommunications Systems FPM Fast Page Mode FPO Fleet Post Office Fq Frequency FQDN Fully Qualified Domain Name (Internet) FQPSK Filtered Quadrature Phase Shift Keying FR (1)Frequency Response FR (2)Final report FRA (1)Forward repair activities FRA (2)Federal Request for Assistance (FEMA) FRA (3)Fixed Radio Access FRCM Federal Regional Coordinating Manager (FEMA) Freq Frequency FRMR Packet control frame: Frame Reject FRN (1)FCC Registration Number FRN (2)Free Radio Network FROPA frontal passage FRP (1)Federal Response Plan (FEMA) FRP (2)Fleet Response Plan FRQ frequent FRS Family Radio Service FRUIT False Reply Uncorrelated In Time FS File Separator (ASCII) FS-1037C Official Federal Telecom Glossary, replaced by ATIS FSB Forward support battalion FSBS (Consolidated) Fixed Submarine Broadcast System FSC Full Scope Command (USAF HF Phase II) FSD Federal Security Director FSE Fire support element FSF Free Software Foundation FSK Frequency-shift keying FSL Forecast Systems Laboratory FSM Facility Status Message FSOC Fairchild Satellite Op Center, Fairchild AFB, WA FSP (1)File Service protocol (Internet) FSP (2)File Slurping Protocol FSP (3)Flaky Stream Protocol FSP (4)FTP's Sexy Partner FSQ Fast Simple QSO (Amateur MFSK mode) FSRAM Fast Static Random Access Memory FSS Fixed-Satellite Service FST Forward surgical team FSTS Federal Secure Telecommunications System FSU Former Soviet Union FT (1)Terminal Forecast (weather) FT (2)Feet ft foot FTA F--- The Army FTAM File Transfer Access and Management FTG F--- The Guard FTI Fixed Target Indicator FTP File Transfer Protocol FTS Federal Telephone System FTW F--- The World FU Smoke (from French) FUBAR [Fouled] Up Beyond All Recognition FUD Fear, Uncertainty, Doubt (computer marketing technique) FV Fishing Vessel FVLF Fixed, Very Low Frequency FW Fighter Wing (USAF) FWA Fixed Wireless Access fwd forward FWE Fighter Wing Equivalent FWIW For What It's Worth FWOC Fleet Weather and Oceanographic Centre (UK) FY Fiscal Year FYEO For Your Eyes Only FYI For your information FZ freezing FZRANO freezing rain sensor not available G (1)Conductance, reciprocal of R, in mhos, ohm backwards G (2)Gust G/T "G over T", antenna gain divided by noise temperature G1 Asst. Chief of staff, personnel (US Army) G2 Asst. Chief of staff, intelligence (US Army) G3 Asst. Chief of staff, operations and plans (US Army) G4 Asst. Chief of staff, logistics (US Army) G5 Asst. Chief of staff, civil affairs (US Army) G6 Asst. Chief of staff, information mgmt. (US Army) GA (1)CW prosign: go ahead GA (2)CW brevity code: Good Afternoon GaAs Gallium Arsenide GaAsFET Gallium Arsenide Field Effect Transistor GACC Geographic Area Coordination Centers (USFS) GAFRAN Stationary German Air Force GAGAN GPS Aided Geo Augmented Navigation (India) GAK Government Access to Key GALEX Galaxy Evolution Explorer (NASA) GaN Gallium Nitride Gantsec Greater Antilles Section (US military/federal, out of Puerto Rico) GAO General Accounting Office (US Government) GATM Global Air Traffic Management GATR ground-to-air transmitter/receiver GATX General American Transportation Corporation, tank & hopper car lessor GBAS Ground Based Augmentation Service GBDL Ground Based Data Link GBI Ground-Based Interceptor GBL Ground-Based Laser Gbps Gigabytes per second GBR Ground Based Radar GBS (1)Global Broadcast System GBS (2)Ground Based Sensor GCA Ground Controlled Approach GCAS Ground Collision Avoidance System GCBS Ground Control Bombing System GCC Ground Component Commander GCCS (0)Two different systems: GCCS (1)Global Command Control System, obsolete US Air Force GCCS (2)Global Command & Control System, 1992 data network plan to replace WWMCCS computers GCCS-J Global Command & Control System - Joint GCHQ Government Communication Headquarters ("G;" UK comint) GCMP Guam Composite Broadcast (obsolete USCG) GCN (1)ground communications network GCN (2)ground control network GCSS Global Combat Support System GD CW brevity: Good Day GDIP General Defense Intelligence Program GDO Grid/Gate Dip Oscillator GDOC Geographical Display Operations Computer GDR Ground Data Reduction GDSS Global Decision Support System GE (1)General Electric GE (2)CW brevity: Good Evening GE (3) Guerra Elettronica (Italian for Electronic Warfare) GENSER (1)General Security Regulations GENSER (2)general service GENTEL General Telephone Company GEO Geosynchronous Earth Orbit GEODSS Ground-based electro-optical deep space surveillance GEOS (1)Geodynamic experimental ocean satellite GEOS (2)Geomagnetic earth observation system GEOS (3)Graphic Environment Operating System GEP Ground Entry Point GES Ground Earth Station GETS Government Emergency Telecommunications Service (US NCS) GFA Graphical Area Forecast GFAE Government-furnished aerospace equipment GFDL Geophysical Fluid Dynamics Laboratory GFE (1)Government-furnished equipment GFE (2)God-Furnished Equipment (ionosphere) GFI (1)Government-furnished information GFI (2)Ground Fault Interrupter GFM Government-furnished material GFP (1)Government Furnished Property GFP (2)Government-furnished part GFS Global Forecast System (US wx model) GG Transmission is in German GHFS Global High Frequency System (US Air Force) GHz GigaHertz GI (1)Government Issue GI (2)Old slang, from above: U.S. soldier GID Group Identification GIF Graphics Interchange Format, first used on CompuServe GIGO Garbage In, Garbage Out; first rule of computing GIMP GNU Image Manipulation Program, a nested acronym GIS Geographical Information System GKS Graphical Kernel System GLOB Ground Loving Old B-----d (KC-135) GLONASS Global Navigation Satellite System (Russian GPS) GLS GNSS Landing System GM (1)CW brevity code: Good Morning GM (2)General Motors GM (3)General Manager GM (4)Guided Missile GMDSS Global Maritime Distress & Safety System GMF (1)Ground Mobile Force GMF (2)Government Master File (frequencies) GMI General Military Intelligence GMRA Great Man-made River Authority (Libya) GMRS General Mobile Radio System GMS Geostationary Meteorological Satellite (Japanese) GMSK Gaussian Minimum Shift Keying GMT (1)Greenwich Mean Time (obsolete, still UK's name for standard time) GMT (2)Ground Moving Target GMTI Ground Moving Target Indication GNA Gulf News Agency GNC (1)guidance and navigation computer GNC (2)guidance, navigation and control gnd ground GNDCON Ground Control GNSS Global Navigation Satellite System gnu Gnu's Not Unix, a freeware op-system (recursive acronym) GO General Officer GOA Gone on Arrival (police) GOES (1)Geosynchronous Oceanic & Environmental Satellite GOES (2)Geostationary Operational Environmental Satellite GOGO government-owned, government-operated GOJ Government of Japan GORIZONT Moscow State University Geostationary Monitor satellite GOSIP Government Open Systems Interconnection Profile (UK & US) GOTS Government-off-the-shelf gov Government site (Internet) GOWON Gulf Offshore Weather Observing. Network gp Group GPM Gallon(s) per minute GPO (1)Government Printing Office (US) GPO (2)General Post Office GPR Ground Penetrating Radar GPRS General Packet Radio Service GPS Global Positioning System GPS RTK Global Positioning System Real-Time Kinematics GR Hail (from French) GRADU Gradual weather change GRC General Radio Communications (AN/GRC-xxx) GRDCUS Gulf Range Drone Control Upgrade System grep Global Regular Expression, Print; Unix text search GRI Group Repetition Interval (Loran) grp Group GRT Gross register tonnage GS (1)General support GS (2)Group Separator (ASCII) GS (3)small hail and/or snow pellets GS (4)Ground Stop GS (5)Ground Station GSA General Services Administration (US) GSAC Ground support associate contractor GSC (1)Ground systems controller GSC (2)Ground support contractor GSCO Ground systems control officer GSD General support division GSE Ground support equipment GSF GPS support facility GSFC Goddard Space Flight Center, Greenbelt, MD GSM Global System for Mobile communications (EU cell phone mode) GSMP General Switch Management Protocol GSO Geostationary Satellite Orbit GSTS Ground-based surveillance and tracking system G-SWF Gradual Shortwave Fadeout (ionospheric disturbance) GTC Greek Telegraphy Club, aka SV-CW-C GTK GIMP Tool Kit, a deeply nested acronym gTLD generic top-level domain GTO (1)geosynchronous transfer orbit GTO (2)fast car made by Ferrari ("Gran Turisimo Omologato") GTO (3)not quite so fast car made by Pontiac GTOC Geosynchronous transfer orbit capability G-TOR Golay Transmissions Over Radio (Kantronics version of PACTOR) GTS Global Telecommunication System (WMO) GUHOR Informal: "I don't hear you" (Loosely, from Russian prosign) [~] GUHOR Stick (1)Informal: Net diagramming tool used in Cold War COMINT GUHOR Stick (2)Wouff Hong substitute (see Wouff Hong) GUI Graphical User Interface GUID Globally Unique Identifier GVAR GOES Variable GW (1)Gigawatt GW (2)CW brevity code: Good Evening GW (2)Ground wire GWARC General World Administrative Radio Conference GWEN Ground wave emergency network (VLF strategic net) GWT Gross Weight Tonnage H (1)Henry (unit of inductance) H (2)Magnetic field h/w Hardware H24 All 24 hours; station operates continuously HA ("Hotel Alpha") human remains HAARP HF Active Auroral Research Program HAAT Height Above Average Terrain HAC (1)higher authority communications(USAF) HAC (2)heading alignment circle (NASA) HAC (3)Hughes Aircraft Company HAES High Altitude ELINT System HAF Headquarters Air Force HAL (1)High-order Assembly Language (space shuttle computers); named for: HAL (2)Heuristically programmed Algorithmic Computer (2001: A Space Odyssey) HAMP Horizontal Avionics Modernization Planning HAMS Hilltop Amateur Mastertie System; old, big SoCal 440 MHz system HAR Highway Advisory Radio HARCO Harris Radio Company, makes HF setups HARM High-Speed Anti-Radiation Missile HAS Hardened Aircraft Shelter HASA High Altitude SIGINT Architecture HBD (1)Has Been Drinking (police) HBD (2)Hot Box Detector (railroad) HBI Horizontal Blanking Interval (TV) HBO Home Box Office (TV network) HBS Heart Beat Signal (Australian Internet) HBT Heterojunction Bipolar Transistor HBT Heterojunction Bipolar Transistor HC-ARQ Hagelin-Cryptos simplex teleprinter system HCI Human-Computer Interface HCJB Heralding Christ Jesus' Blessing (callsign) HCP Health and comfort package H-CPM Harmonized Continuous Phase Modulation HD (1)Hard Disk HD (2)High Density HD (3)High Definition HDB High-Density Bipolar HDD (1)Hard Disk Drive HDD (2)Heads Down Displays HDLC High-level Data Link Control, old synchronous computer protocol HDOP Horizontal Dilution of Precision (DGPS) H-DQPSK Harmonized Differential Quadrature Phase-Shift Keying HDR High Data Rate HDS Hard Disk Subsystem HDSL High-rate Digital Subscriber Line HDTV High-Definition Television HDX Half-duplex HE (1)high energy HE (2)high explosive HE-AAC High-Efficiency Advanced Audio Coding HEAR Hospital Emergency Alert Radio (SoCal) HEMP High-altitude electromagnetic pulse HEMT High-electron-mobility transfer HEMTT Heavy expanded mobility tactical truck HEO (1)high earth orbit HEO (2)highly elliptical orbit HEP Head End Power (railroad locomotives) HERE Hazards of Electromagnetic Radiation to Equipment HERF High-Energy RF (weapons) Hertz Unit of frequency, named for Heinrich Hertz, 1Hz=1 cps HES Hurricane Evacuation Study HETS (1)heavy equipment transporter system HETS (2)heterodynes [~] Hex Hexadecimal number notation, base 16 HF High Frequency (3-30 MHz) HF-ALE High Frequency Automatic Link Establishment HFBC High-Frequency broadcasting HFCC High-Frequency Coordination Conference HFDL High-Frequency Data Link, single-tone digital aero mode HFDLP HF Data Link Protocol HFDR HF Data Radio HFDU HF Data Unit HFGCS High Frequency Global Communications System (Scope Command) HFIA HF Industry Association HFMOD Australian Defence Force High Frequency Modernisation Project HFNC HF Network Controller HFNPDU HFDL: High Frequency Network Protocol Data Unit HFO (1)High-Frequency Oscillator HFO (2)Honolulu Forecast Office HFS Hierarchical File System HFSWR High-Frequency Surface-Wave Radar HHS (Dept. of) Health & Human Services HHT (1)Hand-Held Terminal HHT (2)Hand-Held Tester HI CW brevity code: a laugh (all dits, easier to send than "HA") HICOM High Command net (US Navy) HIDAR High Data Rate HIFER High-Frequency Experimental Radio (low-power ~13.5 MHz) Hi-fi High Fidelity (audio) HIPAS High-Power Auroral Stimulation HIPPI High Performance Parallel Interface HIRF High Intensity Radiation Fields HISCAT High-latitude, High-altitude, High-power, High-frequency, High-performance, Heating and Ionospheric Scatter facility (research) HITRON Helicopter Interdiction Tactical Squadron (US Coast Guard) HIWAS Hazardous Inflight Weather Advisory Service HJ ("Hotel Juliet") Hijack HK Handle Key (Windows registry) HKCC Handle Key, Current Configuration (Windows registry) HKCR Handle Key, Classes, Root (Windows registry) HKCU Handle Key, Current User (Windows registry) HKDD Handle Key, Dynamic Data (Windows registry) HKEY Handle to a KEY (Windows Registry) HKG Hong Kong (old country code) HKLM Handle Key, Local Machine (Windows registry) HKTI Hong Kong Telecom International HKU Handle Key, Users (Windows Registry) HM Her Majesty HM01 Hybrid Mode #1; Cuban numbers combining voice and digital HMCS Her Majesty's Canadian Ship HMMWV High mobility, multipurpose wheeled vehicle (hummvee) HMS Her Majesty's Ship HND Honduras (country code) HNG Hungary (country code) HNG-FEC Hungarian diplo FEC teleprinting system HNMP HF Network Management Protocol HNS Host nation support HOLF Helicopter Outlying Landing Field HP (1)High Pass (filter circuit) HP (2)Highway Patrol hp Horsepower Hpa Hectopascal HPC Hydrometeorological Prediction Center, MD HPE CW brevity code: "Hope to..." HPG Hardcopy Processor Group HPI High-Priority Intercept (global HF comint system) HPM High Power Microwave HPTS High-Power Transmitting System (TACAMO) HQ Headquarters HQAN HAVE QUICK A-Net HQDA Headquarters, Department of the Army HR High Resolution hr Hour HR Hybrid Receive HRC Harmonically Related Carrier (CATV channel scheme) HRCS High Resolution Camera System HRMP HF Relay Management Protocol HRPT High Resolution Picture Transmissions HRR High Resolution Radar hrs Hours HRT (1)Hostage Rescue Team (FBI) HRT (2)Hrvatske Radio Televizije (Croatian) HRV Croatia (country code) HSAL High Speed Algebraic Logic HSFB High Speed Fleet Broadcast HSI Hyperspectral Imaging HSIP H Camera Sensor Improvement Program HSSP HF Station Status Protocol HST (1)Hawaiian Standard Time HST (2)Hubble Space Telescope HT (1)Handie-talkie, a hand-held radio HT (2)Horizontal Tab (ASCII) HTI (1)Haiti (country code) HTI (2)Hostile Target Identification HTML Hypertext Markup Language (world wide web) HTS High Temperature Superconducting HTTP HyperText Transmission Protocol (WWW) HTTPD HTTP Daemon (Unix) HTTP-NG HTTP Next Generation HTTPS (1)HTTP Server HTTPS (2)HTTP with Secure Sockets Layer HUD Heads-up Displays HULTEC Hull to Emitter Correlation HUMINT Human Intelligence (spies!) HVAC Heating, Ventilation, Air Conditioning HVAR High-Velocity Aerial Rocket HW CW brevity code: "How do you copy me?" HWRF Hurricane Weather Research and Forecasting (model) hx Signal is a harmonic HYDROLANT US warnings for Atlantic and east HYDROMET Hydro-Meterological bulletin or warning HYDROPAC US warnings for Pacific Ocean and west Hyperfix Hyperbolic Radio Navigation System, obsolete HZ haze Hz Hertz (a "cycle per second") I (1)Current (in amperes, amps) I (2)Packet designator: information frame I (3)Italy (country code) I/O Input/Output (computers) I/Q In-phase/ Quadrature i18n Alphabet scheme for multi-lingual computer programs [~] IA (1)Information Assurance IA (2)Italian Army IA (3)Short for IATSE, the movie/theatrical production union IA (4)Information Attack IAAFA Inter-American Air Forces Academy IAB Internet Architecture Board IAC International Analysis Code (weather codes FM-45, FM-46) IADS Integrated Air Defense System IAEM International Association of Emergency Managers (was NCEM) IAF Italian or Irish air force IAG Imagery Analysis Group IAGA International Association of Geomagnetism and Aeronomy IAIP Information Analysis and Infrastructure Protection IANA Internet Assigned Numbers Authority IAP International AirPort IAPS I Am Pretty Sure IARN International Amateur Radio Network IARP International Amateur Radio Permit (to operate overseas) IARU International Amateur Radio Union IAS (1)Image Access Service IAS (2)Indicated Air Speed IAS Intelligence Analysis System IATA International Air Transport Association IAU International Astronomical Union IAVTR Integrated Audio Visual Transmitter/ Receiver IAW In accordance with IBC (1)International Broadcast Center (Olympics) IBC (2)Italian Broadcasting Corporation IBCT Initial Brigade Combat Teams IBDL Inter Battery Data Link IBM (1)International Business Machines (company) IBM (2)de facto PC standard, though few are true blue IBOC In-band, on-channel (digital broadcasting) IC (1)Integrated circuit (chip) IC (2)Incident Command IC (3)Ice crystals IC (4)In-cloud lightning ICAO International Civil Aviation Organization ICAP Internet Calendar Access Protocol ICAS Intermittent Commercial and Amateur service (rating) ICBM Intercontinental Ballistic Missile ICD Interface Control Document ICE (1)Immigration and Customs Enforcement ICE (2)Intrusion Countermeasures Electronics ICIS Interagency Communications Interoperability System (SoCal) ICM Intelligence Correlation Module ICMP Internet Control Message Protocol ICNIA Integrated Communications Navigation IFF Avionics ICNIS Integrated Communication Navigation and ID System ICOM (1) Intercom ICOM (2) Japanese radio mfr [~] ICOM (3) Integrated COMSEC ICON Image Communication and Operations Node ICP Internet Cache Protocol ICPO International Criminal Police Organization, see INTERPOL ICQ "I Seek You" (Internet message program) [~] ICRC International Committee of the Red Cross ICS Incident Command System ICSTIS Independent Committee for the Supervision of Standards of Telephone Information Services (UK) ICW interrupted continuous wave ID (1)Identification ID (2)Inside Diameter IDAS (1)Integrated Air Defense System IDAS (2)ICOM Digital Advanced System IDASS Integrated Data Analysis System for Spacecraft IDCP ID Data Combining Process IDE (1)Intelligent Drive Electronics (small HD standard) IDE (2)Integrated Developer Environment IDEA International Data Encryption Algorithm IDECM Integrated Defensive ECM I-DGS Interim-Deployable Ground Station IDLH Immediate Danger to Life and Health IDLM Interference Detection, Locating, and Mitigation IDM Improved Data Modem IDN Internationalized Domain Names IDPS Interim Digital Processing System IDSL ISDN Digital Subscriber Line IEC International Electrotechnical Commission IED (1)Improvised Explosive Device IED (2)Imitative electronics deception IEE (1)Institute of Electrical Engineers (US), merged with IRE IEE (2)Institution of Electrical Engineers (UK) IEEE Institute of Electrical & Electronics Engineers IETF Internet Engineering Task Force IF Intermediate Frequency (of a receiver) IFE Inflight emergency IFF (1)Identification, Friend or Foe IFF (2)Logic operation: "if and only if" IFIM International Flight Information Manual IFK Incremental Frequency Keying IFK+ Offset Incremental Frequency Keying IFL International Frequency List, ITU doc on fiche or 2 CDs IFOR Implementation Force ("UN peacekeepers") IFP Image Formation Processor IFPFP Individual Flight Plan From this Point IFPS Interactive Forecast Preparation System IFR (1)Instrument Flight Rules IFR (2)"I Follow Roads" IFRB International Frequency Registration Board IFRC Int'l Federation of Red Cross/Red Crescent IFSAR Interferometric Synthetic Aperture Radar IGBT Insulated Gate Bipolor Transistor IGDL Interoperable Ground Data Link IGMP Internet Group Management Protocol IGMP Internet Group Management Protocol IGP Interior Gateway Protocols IGRP Interior Gateway Routing Protocol IGY International Geophysical Year, big 50's research interval IHFR Improved high frequency radio IHO International Hydrographic Organization IHS Internal Hostile Structured threat IHU Internal Hostile Unstructured threat IL Intermediate Language (Object-oriented computing) ILC Integral Locomotive Computer (railroad) ILEAS Illinois Law Enforcememt Alarm System ILS Instrument Landing System IM (1)Intermodulation, causes spurious signals or distortion IM (2)Integrity Monitor (DGPS) IMA Individual Mobilization Augmentee (FEMA) IMAP Internet Message Access Protocol IMBE Improved Multi-Band Excitation IMC Internet Mail Consortium IMD Intermodulation Distortion IMETS Integrated Meteorological System IMHO In My Humble Opinion (Internet) IMI CW prosign: interrogative; more often written "?" IMINT Imagery Intelligence IMIS Integrated Maintenance Information System IMM Image Manifest Message IMN Iraqi Media Network IMO (1)International Maritime Organization, part of UN IMO (2)In My Opinion (Internet) IMS Integrated Maritime Surveillance IMSA International Municipal Signal Association IMSI International Mobile Subscriber Identity IMSP Internet Message Support Protocol IMTS Improved Mobile Telephone System IN (1)Intelligent Network IN (2)Indian Navy IN (3)Intelligence in inch INA Iraqi News Agency IND India (country code) indiv individual(s) INEFC Interagency National Emergency Fire Cache INFOSEC Information systems security ING International Notification Group(of IRAC) inHg inch of Mercury (air pressure) INMARSAT Intl. Maritime Satellite Org, a consortium, leases bandwidth on Marecs, Intelsat, Marisat for ship use. INMARSAT-A Inmarsat mobile voice/data terminal INMARSAT-B Improved version, replaced A INMARSAT-C Data-only INMARSAT terminal, also for SAFETYnet INMARSAT-E INMARSAT EPIRB INMARSAT-M INMARSAT terminal, voice only, not GMDSS-compliant INO Indian Ocean (MWARA) InP Indium Phosphide INS (1)Immigration & Naturalization Service (US, now part of ICE) INS (2)Inertial Navigation System INS (3)Indonesia (country code) INS (4)Internal Non-Hostile Structured threat INSCOM US Army Intelligence and Security Command INT (1)Interrogative (precedes a question) INT (2)International INT (3)Interrupted (transmission) INT (4)Interrupt (computer processing) intel Intelligence INTELCAST Intelligence Broadcast INTELNET Intelligence Network Internet Global interconnection of regional nets using TCP/IP InterNIC Internet Network Information Center INTERPOL International Criminal Police Organization Intl International, internal INU Internal Non-Hostile Unstructured threat IOC Index of co-operation (a fax parameter) IOD Issue Of Data (DGPS) IOM Installation, operation and maintenance IONCAP IONospheric Communications Analysis and Prediction, original prediction algorithm, still used IOR Indian Ocean Region IOS Indian Ocean Station (NASA) IP Internet Protocol IPA Intermediate power amplifier IPB Intelligence Preparation of the Battlefield IPCP Internet Protocol Control Protocol IPF Intelligence Processing Facility IPI Intelligent Peripheral Interface IPIR Initial Photo Interpretation Report IPIX Interface Processor for Imagery Exchange IPL Image Product Library IPng IP next generation IPS (1)Inches per second IPS (2)Ionospheric Prediction Service (Australia, original name for space weather agcy) IPSec Internet Protocol Security IPSS International Packet SwitchStream, now GNS (UK) IPT Integrated Program Team IPTV Television via IP protocol (Internet TV) IPX Internetwork Packet Exchange (Novell) IQ In-phase/Quadrature IQSY International Year of the Quiet Sun, 1960's research interval IR (1) Infrared IR (2) Instrument route (numbered military training route) IRA International Reference Alphabet IRAC Interdepartment Radio Advisory Committee (part of US NTIA) IRBM Intermediate Range Ballistic Missile IRC (1)International Reply Coupon IRC (2)Internet Relay Chat, world's primo time waster IRC (3)International Red Cross IRC (4)Incrementally Related Carrier (CATV channel scheme) IRC (5)International Record Carrier IRCA International Radio Club of America IRCCM Infrared Counter-Countermeasures IRCM Infrared Countermeasures IRE Institute of Radio Engineers, now IEEE IRI Ionospheric Research Instrument, transmitter part of HAARP IRINT Infrared intelligence IRIS Improved Radio Ionospheric Sounder IRL Ireland (country code) IRN Iran (country code) IRNSS Indian Regional Navigational Satellite System IRQ (1)Interrupt request (computer hardware) IRQ (2)Iraq (country code) IRRM Image Recording Request Message IRRS Italian Radio Relay Service IRS (1)Information Receiving Station (SITOR) IRS (2)Internal Revenue Service (US) IRS (3)Infernal Revenue Service (U$) IRSS Infrared Surveillance System IRST Infrared Search and Track IS (1)Interval signal IS (2)Intermediate Standard, formerly RS IS (3)Information System IS (4)Islamic State; name taken by terrorist group IS-136 ANSI-136 multiple access standard ISA (1)Industry Standard Architecture (PC-AT bus) ISA (2)In-Session Activation (telco) ISABPS Integrated Submarine Automated Broadcast Processor System ISAM Indexed Sequential Access Method ISARC Intelligence, Surveillance, and Reconnaissance Cell ISB (1)Independent Sideband ISB (2)Intermediate Staging Base ISC Initial Scope Command (phase I) ISD Inverted Scanning Direction (radiofax) ISDB Integrated Services Digital Broadcasting (Japanese digital TV/Radio) ISDL ISDN Digital Subscriber Line ISDN Integrated services & data network (telco) ISEC Information Systems Engineering Command ISF International Science Foundation ISI Inter-Symbol Interference ISIL Islamic State of Iraq and the Levant ISIS Islamic State of Iraq and Syria ISM Industrial, Scientific, Medical (RF devices) ISMLS Interim Standard Microwave Landing System ISO (1)International Organisation for Standardisation ISO (2)International Organizations for Standardization ISODE ISO Development Environment ISP Internet service provider ISR In-System Reprogrammable ISS (1)Information Sending Station (SITOR) ISS (2)International Space Station ISSO (1)Information System Security Officer ISSO (2)Information Systems Security Organization (US) ISTR I Seem To Recall IT (1)Information Technology IT (2)Information Technology Directorate (FEMA) ITA International Telegraph Alphabet ITA1 International Telegraph Alphabet #1 (Old cablegrams, obsolete) ITA2 International Telegraph Alphabet #2 (Baudot double-shift) ITA3 International Telegraph Alphabet #3 (7-bit ARQ) ITA4 International Telegraph Alphabet #4 (FM VFT) ITER Improved Triple Ejector Rack ITFS Instructional Television Fixed Service ITO Installation transportation office ITS (1)Institute for Telecommunication Sciences ITS (2)Intelligent Transportation Systems ITU International Telecommunications Union ITU-R ITU Sector for Radiocommunications, old CCIR ITU-R M.493-6 - Protocol for maritime Digital Selective Calling ITU-T International Telecommunications Union - Telecommunication Standardization Sector ITU-T ITU Sector for Telecommunications, old CCITT ITU-TSS ITU Telecommunications Standards Section, old CCITT ITWS Integrated Terminal Weather System IUGG International Union of Geodesy and Geophysics IUSS Integrated Undersea Surveillance System IUWDS International Ursigram and World Days Service IVAS Inward Voice Activated Services (telco) IVCS Integrated Voice Communication Systems IVTT Integrated VERDIN Transmit Terminal IW Information Warfare IWG Interoperability Working Group (SHARES) IWS Information Warfare Squadron IWTS Integrated Terminal Weather System IXS Information Exchange System j Vector J/S Jamming to signal ratio J2 Intelligence directorate at a joint headquarters J2B Single sideband, suppressed carrier tone teleprinting (emission) J3E Single sideband, suppressed carrier AM radiotelephony (emission) J4 Logistics directorate at a joint headquarters JAA Joint Aviation Authorities (Europe) JAFO Just Another F[ine] Observer JAG Judge Advocate General JALBTCX Joint Airborne Lidar Bathymetry Technical Center of Expertise JAN Joint Army/Navy (spec) JANA Jamahiriyah News Agency JANET Joint Academic NETwork (UK) JAR Joint Aviation Requirements (Europe) JARL Japan Amateur Radio League JARS Joint Air Reserve Station JASORS Joint Advanced Special Operations Radio System JATACS Joint Advanced Tactical Command and Control System JATCC Joint Air Traffic Control Center JAWS Juneau Airport Wind System JAWSAT Joint Air Force-Weber State University Satellite JCS Joint Chiefs of Staff JCSE Joint Communications Support Element JDF Japanese Defense Force JDISS Joint Deployable Intelligence Support System JEDEC Joint Electronic Device Engineering Council Jeep Believed from "General Purpose" military vehicle, now a tradename JFA Japan Fisheries Association JFC Joint force commander JFET Junction Field-Effect Transistor JIATF-E Joint Interagency Task Force, East (incorporates JTF-4) JIATF-S Joint Interagency Task Force, South (inc. JTF-6) JIATF-W Joint Interagency Task Force, West (inc. JTF-5) JIC Joint Information Center JINTACCS Joint Interoperability of Tactical Command and Control Systems JIT Just In Time (JAVA Compiler, proprietary to Sun) JITC Joint Interoperability Test Command (US) JIVE Jamming and Interception Vulnerability Estimator JJ (1)Joprep Jiffy (obsolete SAC weather report form) JJ (2)Transmission is in Japanese JJY Japanese standard frequency & time station [~] JMA Japan Meteorological Agency JMC (1)Joint movement center JMC (2)Jamaica (country code) JMPA Joint Military Postal Agency JMRO Joint medical regulating office JN Japanese Navy JOC Joint Operations Center JOPES Joint Operations Planning and Execution System JOPREP Joint Operations Report JORN (1)Jindalee Operational Radar Network (Australian OTH-B) JORN (2)Jindalee OTH Radar Network JOSAC Joint Operational Support Airlift Center JOTS Joint Interoperability Targeting System JOVIAL Jules' Own Version of the International Algebraic Language, once used by USAF JP (1)Joint publication JP (2)Jumper (connection) JP4 Jet Propulsion #4 (military jet fuel) JPATS Joint Primary Aircraft Training System JPEG Joint Photographic Experts Group (lossy compression for pictures) JPL Jet Propulsion Laboratory, CA (NASA) JPNIC Japanese Network Information Center JRCC Joint Rescue Coordination Center JRTC Joint Readiness Training Center (Ft. Polk, LA) JSC Johnson Space Center, TX JSC Joint Spectrum Center JSF Joint Strike Fighter JSMSw Joint Spectrum Management Spectrum for Windows (software) JSORS Joint Advanced Special OPS Radio System JSTARS Joint Surveillance Target Attack Radar System, aka "Joint STARS," E-8 surveillance aircraft JSU All Japan Seamen's Union JTF Joint Task Force, usually US "War on Drugs" JTF-4 Caribbean drug interdiction unit, out of Key West, part of JIATF-E JTF-5 Pacific coast drug unit, part of JIATF-W JTF-6 South & Central America drug unit, part of JIATF-South JTFEX Joint Task Force Exercise JTIDS Joint Tactical Information Distribution System JTRS Joint Tactical Radio System JU JTIDS Unit (net member, like a voice "PU," only in Link-11) JUH-MTF Joint user handbook for message text format JWICS Joint Worldwide Intelligence Communications System K (1)1024 (decimal) of anything (loosely from hexadecimal) K (2)CW prosign: "Go Ahead," technically an "Invitation To Transmit" k A thousand of anything, in decimal (short for kilo) K Index Logarithmic, 3-hourly geomagnetic activity reading k/c Kilocycles K/cs Kilocycles per second = kiloHertz KA9Q Packet radio protocol, from callsign of its inventor [~] KAM Kantronics All-Mode (packet/digital controller) KAWN Identifier attached to AWN weather products, as relayed by several HF stations KB Keyboard kB Kilobit, kilobaud kb/s kilobits per second KBD Keyboard kBd Kilobaud Kbps Kilobits per second KBS Korea Broadcasting System kc Kilocycles per second, now kHertz KCAS Knots Calibrated Air Speed KCNA Korean Central News Agency kcs Kilocycles per second, now kHertz KDU Keypad-Display Unit KFOR Kosovo Forces KGB Komitet Gossudarstwennoy Besopasnostij (transliterated from Russian by Klingenfuss), old USSR comint, replaced by FAPSI KH Keyhole, optical recon satellite, KH-12 resembles Hubble kHz KiloHertz KIPM Illuminati Primum Materium (Pirate) KISS Keep it simple, stupid (packet radio mode/engineering golden rule) km kilometer kMc kilo-Megacycle, now GigaHertz knot Nautical mile/hour [~] KNRM Koninklijke Nederlandse Redding Maatschappij (Dutch SAR org.) KOR (South) Korea (country code) Kp Planetary K index kph kilometer per hour KRE (North) Korea (country code) KSC Kennedy Space Center, Cape Canaveral, FL KSCPAO Kennedy Space Center Public Affairs Office (NASA) ksh Korn shell (Unix) KSR Keyboard Send-Receive kt knot (nautical mile per hour) KT knots KTAS Knots True AirSpeed KTS knots Ku-band 12-18 GHz microwave band kV Kilovolt KVA KiloVolt-Amp(s); can <> kW in highly reactive circuit kW Kilowatt L Inductance (in Henrys) L left (with reference to runway designation) L2TP Layer 2 Tunneling Protocol LA Low altitude Ladar Laser Radar LAHSO Landing And Hold Short Operations LAN Local Area Network LANL Los Alamos (NM) National Laboratory LANTAREA USCG Atlantic Area LANTIRN Low Altitude Navigation and Targeting Infra Red for Night LAO Laos (country code) LAPD (1)Link Access Procedure D-Channel LAPD (2)Los Angeles Police Department LAPM Link access protocol for modems LA-RICS Los Angeles Regional Interoperable Communications System LASER Light Amplification by Stimulated Emission of Radiation LAST last observation before a break in coverage at a manual station LAU Launcher Adapter Unit LBA Logical Block Addressing (Disk access) LBAR Limited area BARotropic (NCEP weather model) LBN Lebanon (country code) LBR Liberia (country code) LBY Lybia (country code) LC Limited Coastal (service) LCA St. Lucia (country code) LCAC Landing Craft, Air-Cushioned (large hovercraft) LCC Launch Control Center LCD Liquid Crystal Display LCMP Atlantic Composite Broadcast LCP Link Control Protocol (PPP) LCS Limited Coastal Station LCU Landing Craft, Utility (US Army) LD Lethality Database (hazmat; often followed by percentage) LDAP Lightweight Directory Access Protocol LDF Lightweight digital facsimile LDOC Long Distance Operational Control (civil aviation) LDP Landing Decision Point LDR (1)Low Data Rate LDR (2)Loader LDTWA Long Dual Trailing Wire Antenna (TACAMO) LE Law Enforcement LEARN Law Enforcement Amateur Radio Network LEASAT Leased Satellite (US military comm) LED Light Emitting Diode LEO Low Earth Orbit ("Little LEO" = a type of mini-satellite) LES Land Earth Station LF (1)Low Frequency (30-300 kHz) LF (2)Linefeed LFMCW Linear Frequency-Modulated Continuous Wave LFMICW Linear Frequency-Modulated Interrupted Continuous Wave LFO Low frequency oscillator LG Logistics Group LGTR Laser Guided Training Round LHCP Left-hand circular polarization LIAR Liar Imitates Apply Recursively (recursive) Lidar Light Detection & Ranging (light "radar") LIE Liechtenstein (country code) LIM (1)Lotus/Intel/Microsoft, original spec for PC extended memory LIM (2)Line interface module LINCOMPREX Link Compression and Expansion, old ACSB system Linux "Linus' Unix," open-source version of Unix LIRL Low Intensity Runway Lights LL Landline, "Lima Lima" LLC (1)Logical Link Control LLC (2)Limited Liability Corporation (US) LLCC Low Level Cloud Center (wx obs) LLNL Lawrence Livermore National Laboratory LLP Limited Liability Partnership (US) LLWAS Low Level Wind Shear Alert System LMAO Laughing My A-- Off (Internet) LMCC Land Mobile Communications Council LMR Land Mobile Radio ln Natural logarithm LNB Low Noise amplifier/Block downconverter LNBF Low Noise amplifier/Block downconverter Feedhorn LNP Local Number Portability (cell phones) LO Local oscillator (of a receiver) LOC (1)lines of communication LOC (2)location log Common logarithm LOGCAP Logistics Civil Augmentation Program LOGPAC Logistics package LOI Low Opportunity of Intercept LOJACK Vehicle locator beacon activated & DF'd by police LOL Laughing Out Loud (internet) LORAC Long Range Accuracy (NASA booster recovery) LORAN Long Range Navigation LORAN-A Discontinued 160m Loran system LORAN-C 100 kHz Loran system LORAN-D Military Loran system LOS (1)Loss Of Signal LOS (2)Line of sight LOTS logistics-over-the-shore LOWFER Low-Frequency Experimental Radio (~164-190 kHz) LP (1)Long Playing (old records) LP (2)Low pass (filter circuit) LP (3)Linking Protection (US mil ALE security) LP (4)Log Periodic (antenna) LPB Logistics preparation of the battlefield LPD Line Printer Daemon LPDA Log Periodic Dipole Array LPDU HDFL: Link Protocol Data Unit LPFM Low-Power FM (broadcasting) LPI Low Probability of Intercept LPM Lines per minute LPR Line Printer LPRS Low-Power Radio Service (FCC) LPT Logistics preparation of the theater LPTV Low-Power TV (broadcasting) LPVA Log Periodic V Array LQA Link Quality Analysis (databursts heard from ALE radios) LR Last Received (message) LRA Landing Rights Airport LRAD Long-Range Acoustic Device LRC (1)Longitudinal Redundancy Check (computing) LRC (2)Logistics and Readiness Center LRCOC Long Range Company Operational Control LS Last Sent (message) LSASS Local Security Authority Subsystem Service (Windoze) LSB (1)Lower Sideband LSB (2)Linux Standard Block LSB (3)Least Significant Bit/Byte LSDIS Light and Special Division Interim Sensor (US Army) LSE Logistics support element LSI (1)Large scale integration (of chips) LSI (2)Locomotive System Integration LST (1)Landing ship, tank LST (2)Local Standard Time LSV Logistic Support Vessel (US Army) LTE Long Term Evolution LTG lightning LTR (1)Letter(s) LTR (2)LOgic Trunked Radio (Johnson) LTRS Letters case (Baudot lower case) LUF Lowest Usable Frequency (varies with path) LUT Local User Terminal LUU Parachute Flare LWR lower LZW Lempel-Ziv-Welch, lossless compression algorithm for data M (1)Mega, meg, a million of anything, or 1,048,576 bytes (hex) M (2)minus, less than M (3)Below zero C M (4)Statute Mile m Meter (39.37 inches) M/S (1)Motor Ship (also MS, M.S.) M/S (2)Mile per second m/s Meter per second M/V Motor Vessel (also m/v) m/v Motor Vessel (also MV) M1FC Model 1 Full Capacity (Air traffic control) mA milliamperes MAC (1)Military Airlift Command, now AMC MAC (2)Medium Access Control (computer networks) Mac Macintosh (computer) MACOM Major command MacTCP TCP/IP package for Macintosh MAFFS Modular Airborne Fire Fighting System (tank for C-130) MAFOR Maritime weather forecast MAGIS Marine Air-Ground Intelligence System mAh miliamp-hour(s) MAIT Major Accident Investigation Team (CHP) MAN Metropolitan Area Network, halfway between a LAN and a WAN MANPAD Man-Portable Air Defense MAP Maghreb Arabe Presse MAPI Mail/Messaging Applications Programming Interface MAPS Mail Abuse Prevention System (Internet) MARAD MARitime ADministration [~] MARC MAchine Readable Catalog MARCEMP Manual Relay Center Modernization Program (USN) MARLIN Mobile Ad-hoc Relay Line-of-sight IP Networking MARO Maritime Air Radio Organization MARS (1)Military Auxiliary Radio System (US) MARS (2)Maritime (mobile) Access & Retrieval System (ITU ship lookup) MARSA Military Assumes Responsibility for Separation of Aircraft MARSEC Marianas Sector (US Coast Guard) [~] MASER Microwave Amplification by Stimulated Emission of Radiation MASH Mobile Army Surgical Hospital, may be obsolete MASM Macro-Assembler (computer code) MATIC Mobility Assessment Test and Integration Center MATS Military Air Transportation Service, became MAC, then AMC MAU Media Attachment Unit, a network transceiver MAVICA Magnetic Video Camera MAYDAY Prosign: Distress traffic follows; repeated 3 times [~] MB Megabyte mb millibar MBCS (1)Multi Byte Character Set (Unicode) MBCS (2)Magnetic Bridge Current Sensor MBDL Missile Battery Data Link MBE Multi-Band Excitation (digital voice) MBKS Multi-Button Key Set (telco) MBO Mailbox MBONE Multicast Backbone Mbps Megabytes per second MBR Master Boot Record ("boot sector") MCA Movement control agency MCC (1)Master Control Center MCC (2)Movement control center MCC (3)Mobile Contingency Communications (USCG) MCFB Multi-Channel Fleet Broadcast MCM Mine Countermeasures MCP (1)Mobile communications package MCP (2)Multimode Communications Processor (packet) MCP (3)Male chauvinist pig MCS Mission Communications System MCS/P Maneuver Control System/Phoenix (US Army) MCVFT Multichannel Voice Frequency Telegraph (multiplex RTTY) MD5 Message-Digest, algorithm 5 (crypto, 128-bit) MDR Medium Data Rate MDS Multipoint Distribution Service MDSU Mobile Diving and Salvage Unit (US Navy) MDT (1)Mobile Data Terminal (usually police) MDT (2)Mountain Daylight Time, US zone includes Rockies MEBA Marine Engineers' Beneficial Association (Union) med medical MEDAFS Mine Warfare Environmental Data Analysis and Fusion System MEDCOM Medical command MEDFER Medium-frequency Experimental Radio (low power ~510-1710 kHz) MEDICAL Voice prosign attached to c/s of vessel with emergency medical supplies or patients, pronounced MAY-DEE-CAL MEDICO Emergency Medical Communications MEDLOG Medical logistics MEL Maximum Elevation (of a spacecraft) MEMA Massachusetts Emergency Management Agency MEOW (1)Maximum Envelope of Water MEOW (2)Maximum Envelope of Winds MER-# Mars Exploration Rover # (NASA) MERCAST MERchant ship broadCAST MEROD Message Entry and Read Out Device (Thales-Racal, see RAC-ARQ) MERS Mobile Emergency Response Support (FEMA) Messenger Mercury Surface, Space Environment, Geochemistry and Ranging MET Meterological Met Office Weather office at a base METAR Meteorological observation code for routine aviation METAREA Meteorological Area, same number as the NAVAREA (see WMO) METARS Plural of METAR Meteo Meteorological METEOMAR Marine weather broadcast (Italy) METOC Meteorological and Oceanographic Centre (Halifax, NS) Metro Meteorological office METSAT Meterological Satellite MF (1)Medium Frequency (300-3000 kHz) MF (2)Multifrequency mf Microfarad MFA Ministry of Foreign Affairs MFD Modulated Fractional Division MFM Modified Frequency Modulation (Miller Coding) MFSK Multiple Frequency Shift Keying MFU Marine Firemen's Union mgt management mH Millihenry MHD Magnetohydrodynamics; behavior of plasmas in magnetic fields, such as the ionosphere and sunspots MHE materials-handling equipment MHFCS Australian Modernised HF Communication System MHS Message Handling System MHz MegaHertz MI (1)Military intelligence MI (2)shallow mi mile (1.6 km) MI5 Directorate of Military Intelligence, group 5 (UK domestic) MI6 Directorate of Military Intelligence, group 6 (UK foreign, aka SIS) MIB Management Information Base MICR Magnetic Ink Character Recognition (as used by banks) MICS Medical Implant Communications Service MID (1)Middle East (MWARA) MID (2)Maritime Identification Digits, country code prepended to MMSI MIDI Music Industry Digital Interface MIDS Multifunctional Information Distribution System MIFG Shallow Fog MIJI Meaconing, Intrusion, Jamming & Interference ("Jammer writeup") Mil (1) Military Mil (2) Milliampere MIL-188-110A/B/C DoD standard, covers single-tone modems MIL-188-141A/B/C DoD standard, covers ALE controllers MIME Multipurpose Internet Mail Extensions, allows attachment of binaries to ASCII text letters MIMS Medical Information Management System min Minute MIN Mobile Identification Number MINIMUF Miniature Maximum Usable Frequency calculator, classic BASIC MUF prediction algorithm MINREX Ministerio de las Relaciones Exteriores (Cuban news agency) MIR Not an acronym; transliteration of Russian for "Peace" MIREX Mir Experiment, amateur robot packet station on Mir MIRL Medium Intensity Runway Lights MIS Management Information Systems MISDN Mobile ISDN MISR Multi-angle Imaging SpectroRadiometer (Terra satellite) MIT Massachussetts Institute of Technology MITO Minimum Interval TakeOff M-JPEG JPEG used for moving pictures (cf JPEG, MPEG) mkr Marker ML Machine language, how computers store instructions MLAT Multilateration [~] MLB (1)Motor Lifeboat MLB (2)Magnetic Longwire Balun MLM Marine Location Marker MLS Microwave Landing System MLSE Maximum Likelihood Sequence Estimator MLSO Mauna Loa Solar Observatory MLT Magnetic Local Time MM Maritime mobile mm Millimeter MMC (1)materiel management center MMC (2)Microsoft Management Console mmf micro-microfarad, changed to picofarad MMP Masters, Mates, and Pilots (Maritime union) MMR Merchant Marine Reserve MMS Maritime Mobile Service MMSI Maritime Mobile Service Identity (code for DSC) MMX Multimedia extensions (microprocessor architecture) MNCS Master Net Control Station MNP Modem Network Protocol MOA Military Operation Area MOAB Massive Ordnance, Air Blast Mob Mobile MOC (1)Mission Operation Center MOC (2)Ministry Of Commerce (Canada) MOC MERS Operations Center (FEMA nested acronym) MOCA Minimum Obstruction Clearance Altitude MoD Ministry of Defence (UK) MOD (1)Ministry of Defense MOD (2)Mobile Offshore Drilling Mod Modification (to radio) [~] Mode 1 Military air squawk, returns mission code Mode 2 Military air squawk, returns unit code Mode 3 Military/civil air squawk, returns 4-digit ATC ID Mode 4 Military air squawk returned by encrypted challenge Mode 5 Military air squawk, like Mode S only encrypted Mode A (1)SITOR-A (ARQ) Mode A (2)Air transponder squawk Mode B SITOR-B (FEC) Mode C Like Mode A, adds altitude information Mode S Air transponder in mode "Select" Modem Modulator/Demodulator MODIS Moderate Resolution Imaging Spectroradiometer (Terra satellite) MODU Mobile Offshore Drilling Update MOI Ministry Of Information MOOTW Military operations other than war MOP (1)Measure Of Performance MOP (2)Ministry Of Petroleum MOPP mission-oriented protection posture (0-4, 4 being full suit) MOS (1)Metallic Oxide Silicon MOS (2)Mitoudt Sound, shooting film with a silent camera MOSAIC Multifunctional On-the-move Secure Adaptive Integrated Communications MOSFET MOS Field Effect Transistor MOSS MIME Object Security Services MOTD Message Of The Day MOTIS Message Orientated Text Interchange Service, ISO version of MHS MOU Memorandum Of Understanding MOV moved/moving/movement MOX Manually Operated Switching MOZ (1)Mozambique (country code) MOZ (2)Mozilla (computer browser) MP (1)Military Police (US) MP (2)Member of Parliament (UK) MP (3)Multiprocessor (computer h/w) MP Magnetopause MP2 MPEG-1 Level 2, replaced by MP4 MP3 MPEG-1 Level 3, CD-quality compression scheme MP4 MPEG-1 Level 4, audio/video compressor MPDU HFDL: Media access Protocol Data Unit MPEG Motion Picture Expert Group, lossy compression for video MPG (1)File extension: MPEG video MPG (2)Miles Per Gallon mph mile per hour MPSA Military Postal Service Agency MPSAP Mobile Public Safety Answering Point MPT Ministry of Post and Telecom MPX Multiplex MR Magnetoresistive MRAP Mine-Resistant Assault-Protected (vehicle) MRAV Multi Role Armored Vehicle MRB Marine Radio Beacon MRC (1)Mobile Radio Communications MRC (2)Morocco (country code) MRCC Maritime Rescue Coordination Center MRE Meal, Ready-to-Eat MRF Medium Range Forecast (NCEP) MRHS Maritime Radio Historical Society (operates KSM) MRO medical regulating office MRS Mountain Radio Service MRS MPA Medium Range Surveillance Maritime Patrol Aircraft MRSC Maritime Rescue Sub-Center MRT (1)Mountain Rescue Team MRT (2)Mauretania MRU Most Recently Used MS Master Station ms millisecond mS millisiemen MS (1)Motor Ship MS (2)Meteor Scatter MS-188 MIL-STD-188, Military telecom standards MSAS MTSAT Satellite Based Augmentation System (Japan) MSB (1)Most Significant Bit/Byte MSB (2)Main Support Battalion MSC Military Seaflift Command (US) MSE (1)Mobile Subscriber Equipment MSE (2)Mean Square Error MSF (1)English standard frequency & time station MSF (2)Medicins Sans Frontiers (Doctors Without Borders) MSFC NASA Marshall Space Flight Center msg Message MSI (1)Maritime Safety Information MSI (2)Marine Safety Information MSIB Marine Safety Information Bulletin MSIS Mass Spectrometer Incoherent Scatter (research) MSK Minimum Shift Keying MSP Maritime Security Program (US) MSR (1)main supply route MSR (2)Mobile Sea Range MSS Mobile Satellite Service MST (1)Mountain (US) Standard Time, zone includes Rockies MST (2)Maintenance support team MSW Ministerstwo Spraw Wewnetrznych (Poland's Interior Ministry) MT (1)Monitoring Times (no longer published) MT (2)mountain(s) MT (3)Mitigation Directorate (FEMA) MTA (1)Message Transfer Agent MTA (2)Metropolitan Transit Authority MTADS Multi-sensor Towed Array Detection System MTBF Mean Time Before Failure MTF medical treatment facility MTI Moving Target Indicator MTMC Military Traffic Management Command mtr Meter, either distance unit or measuring device MTSAT Multi-functional Transport Satellites (Japan) MTTR Mean Time To Repair MTU Maximum Transmit Unit (TCP/IP packet length) MUF Maximum Usable Frequency (varies with path) MULTICS Multiplexed Information and Computing Service; Unix precursor Mung (1) Verb: to Mash Until No Good Mung (2) Verb: to Mung Until No Good (recursive acronym) MURS Multi-Use Radio Service MUX Multiplex, multiplexer mV Millivolt MV Motor Vessel MVS Multiple Virtual Storage (large IBM computers) MW (1)Medium Wave (typically 530-1710 kHz) MW (2)MegaWatt mW MilliWatt MWARA Major World Air Route Area MWP Meteorologist Weather Processor MWR Morale, welfare, and recreation MX Mail Exchange Record mx Music MYA Myanmar (Burma;country code) MYM My Mailbox (packet) MYP Personal Mailbox (packet) N No Change N north N/A not applicable N0N Unmodulated, steady carrier, old "A0" NA (1)North America NA (2)Not applicable, N/A NA Not authorized NAAS Naval Auxiliary Air Station NAB (1)National Assn of Broadcasters NAB (2)Naval Amphibious Base, USN, Coronado, CA (SEALs train there) NABA North American Broadcasters Assn. NABER National Association of Business/Emergency Radio NAC Network Access Code NACES Naval Aircrew Common Escape System NAD 83 North American Datum of 1983 NADC Naval Air Development Center NADEP Naval Air Depot NADGE NATO Air Defence Ground Environment NAEC Naval Air Engineering Center NAF Naval Air Facility (US) NAFB National Assn of Farm Broadcasters NAK Negative Acknowledgment (error in received data, ASCII 21d) NALF Naval Auxiliary Landing Field NALO Naval Air Logistics Office NAM (1)Number Assignment Module (Cellular) NAM (2)North American Mesoscale (wx model) NANP North American Numbering Plan (telco) NAOC National Airborne Operations Center, aka Nightwatch, old NEACP NAR Not According to Routine NARTE Natl Assn of Radio & Telecommunications Engineers NARTEL North Atlantic Radiotelephone NAS (1)Naval Air Station NAS (2)National Academy of Sciences (US) NAS (3)National Airspace System NAS (4)Network Access Server NASA (1)National Aeronautics and Space Administration NASA (2)National Acronym Slinging Agency NASTD National Association of State Telecommunications Directors NAT (1)North Atlantic (MWARA) NAT (2)Network Address Translation NATC Naval Air Test Center NATO North Atlantic Treaty Organization NATOPS Naval Air Training and Operating Procedures Standardization NAV Navigation NAV/COMM Airplane Navigation/Communication radio NAVAID Navigational aid NAVAIR Naval Air Systems Command NAVAREA Navigational Area (IMO/IHO) NAVCEN USCG Navigation Center, VA NAVCOMMAREA Naval Communication Area NAVCOMMSTA Naval Communications Station NAVCOMPARS Naval Communications Processing and Routing System NAVCOMTELCOM Naval Computer and Telecommunications Command NAVMARCORMARS Navy/Marine Corps Military Affiliate Radio Service (US) NAVMTO Navy Material Transportation Office NAVRADTRANSFAC Navy Radio Transmitter Facility NAVSAT NAVigation SATellite NAVTEX Navigational Telex, Navigational Text (518 kHz SITOR-B) NAWAS National Warning System NAWC Naval Air Warfare Center NAWCAD Naval Air Warfare Center Aircraft Division NAWC-WPN Naval Air Warfare Center NAWIP From Russian for "Navigational Warning" [~] NAWS (1)Naval Air Weapons Station NAWS (2)Old group call: Notice to Allied Warships NB (1)Narrowband NB (2)Noise blanker NBC (1)Nuclear, Biological, Chemical (warfare) NBC (2)National Broadcasting Company NBDP Narrowband direct printing (RTTY) NBDPT Narrowband direct printing telegraphy NBF NetBIOS Frames NBFM Narrowband frequency modulation NBR Narrowband Receiver NBS National Bureau of Standards, now NIST NBSV Narrowband Secure Voice NBSVS Narrowband Secure Voice System NC (1)No Connection NC (2)Normally Closed NC (3)National Center NC3A NATO Consultation, Command and Control Agency (Nested acronym!) NCA (1)North Central Asia (MWARA) NCA (2)National Command Authorities, US nuclear "button" NCAR National Center for Atmospheric Research, CO NCC National Coordinating Center for Communications (US DHS) NCCIC National Cybersecurity and Communications Integration Center (DHS) NCCOSC Naval Command, Control and Ocean Surveillance Center NCCS Navy Command and Control System NCDC National Climatic Data Center NCEM National Coordinating Council for Emergency Management, now IAEM NCEP National Center for Environmental Prediction NCFSK Non-Coherent Frequency Shift Keying NCG Nicaragua (country code) NCIC National Crime Information Center, US database of police records NCIS Naval Criminal Investigative Service NCO Non-Commissioned Officer NCPi Netware Core Protocol NCR (1)National Capital Region (US) NCR (2)National Cash Register NCS (1)National Communications System, US government, obsolete NCS (2)Net Control Station NCS (3)Naval Communications Station NCS (4)Network Coordinating Station NCSA National Centre for Supercomputing Applications, developed Mosaic web browser, which became Netscape (Mozilla) NCTAMS Naval Computer and Telecommunications Area Master Station NCTS Naval Computer and Telecommunications System NCTSI Navy Center for Tactical Systems Interoperability (US) NCWF National Convective Weather Forecast ND Nondirectional NDB Nondirectional beacon NDIS Network Driver Interface Specification NDMS National Disaster Medical System NDRS National Distress and Response System NDRSMP National Distress and Response System Modernization Project NDS NUDET Detection System, see NUDET NE Northeast NEACP National Emergency Airborne Command Post, "kneecap," now NAOC NECC National Emergency Coordination Center (FEMA) NECN National Emergency Coordination Network NERC North American Electric Reliability Council (bulk power delivery) NERK Old CW group call, obsolete NESDIS National Environmental Satellite, Data and Information Service NESP Navy EHF Satellite Program NEST Nuclear Emergency Search Team ("Flynest") NET/ROM Network packet radio protocol NetBEUI NetBIOS Extended User Interface NetBIOS Network Basic Input/Output System NEXRAD Next generation of (weather) Radar NextGen Next Generation (FAA) NFCB National Federation of Community Broadcasters (US) NFCC National Frequency Coordinators' Council NFD No Further Details NFO Naval Flight Officer (same as RIO) NFR Navy Fleet Relay (USN secure satcom) NFS Network File System NFWS Navy Fighter Weapons School NGA National Geospatial-Intelligence Agency (ex-NIMA) NGLT Next Generation Launch Technology NGO (1)Nongovernmental organization NGO (2)Near-Geosynchronous Orbit NGO (3)Naval Gunnery Officer NHC National Hurricane Center, i.e. TPC NHK Nihon Hoso Kyokai , Japanese public broadcast co. NHS (1)National Hydrological Service NHS (2)National Health Service (UK) NIC (1)Network Interface Card NIC (2)Network Information Center NiCad Nickel Cadmium (battery) NiCd Nickel Cadmium (battery) NICP National inventory control point NIEX No-Notice Interoperability Exercise (NATO) NIFC National Interagency Fire Center (US forest fire resources) NIFOG National Interoperability Field Operations Guide (DHS) NIFTP Network Independent File Transfer Protocol NIL CW prosign: "No traffic" or "I copy nothing" NIMA National Imagery and Mapping Agency (now NGA) NIMBY Not In My Back Yard (place people want radio towers) NiMH Nickel-metal hydride (battery) NiMh Nickel-Metal-Hydride (battery) NIMS Naval Ionospheric Measuring System (UK) Niner Number nine, to distinguish from five [~] NIPRNET Non-Classified Internet Protocol Router Network (military's own Internet, with SIPRNET) NIS (1)Network Information System NIS (2)Newly Independent States N-ISDN Narrowband ISDN N-ISDN Narrow Band-Integrated Services Digital Network NISO National Information Standards Organisation (US) NISP Networked Information Services Project (UK) NISS National Information on Software and Services (UK) NIST National Institute of Standards & Technology (old NBS) NLM Netware Loadable Module (extension of Novell Netware) NLSP Netware Link Services Protocol NLT No Later Than Nm (1)Nautical Mile(s); about 1.24 statute miles(1.85 km) Nm (2)Nanometer NM Nautical Mile(s) nm Nautical Mile(s) NMA US Coast Guard COMMSTA, Miami, now controlled from NMN NMC (1)National Meteorological Center NMC (2)National Maritime Center NMC (3)Call of US Coast Guard, Pt Reyes, CA NMC (4)Naval Missile Center NMEA National Marine Electronics Assn NMF US Coast Guard COMMSTA, Boston, will be ctld from NMN NMG US Coast Guard COMMSTA, New Orleans, remote from NMN NMN US Coast Guard Communications, Chesapeake, VA NMO US Coast Guard COMMSTA, Honolulu NNCC National Network Control Center (FAA) NNE North-northeast NNNN RTTY/Telex ending characters NNR National Nature Reserve NNTP Network News Transfer Protocol (USENET) NNW North-northwest NO Normally Open NOAA National Oceanic & Atmospheric Administration NOC (1)Network Operation Center NOC (2)Non-Official Cover (now "OGA") NOE Nap-Of-the-Earth (low altitude attack) NOGAPS Navy Operational Global Atmospherics Prediction System NOI Notice Of Inquiry (FCC rulemaking) NOIWON National Operations Intelligence Watch Officers Net NOJ US Coast Guard COMMSTA, Kodiak NOMTS Naval Ordnance Missile Test Center NORAD North American Aerospace Defense Command NORAPS Navy Operational Regional Atmospherics Prediction System NORDO (1)No Radio NORDO (2)Aircraft has no radio (uses visual signals to tower) NORLANT North Atlantic norm normal NOS (1)Amateur version of TCP/IP (Internet protocols) NOS (2)National Ocean Service NOS (3)Network Operating System NOS (4)New, Old-Stock (wine or vacuum tubes) NOSC Naval Ocean Systems Center, San Diego, CA, now NCCOSC NOSIG No Significent Weather NOSPECI no SPECI reports are taken at the station NOTAM Notice to Airmen NP North Pacific (MWARA) NPA Notice of Proposed Amendment NPC Numerical Prediction Centre NPN Negative/Positive/Negative; transistor type NPR National Public Radio (US) NPRM Notice of Proposed Rule Making (FCC) NPS National Park Service (US) NPSC National Process Serving Center (FEMA) NPSTC National Public Safety Telecommunications Council NRA Non-Radar Airspace NRaD Naval Research and Development (US) NRAO National Radio Astronomy Observatory NRC (1)National Radio Club NRC (2)Nuclear Regulatory Commission (US) NREN National Research and Education Network, faster Internet successor for research sites NRI Net radio interface NRK Norsk Rikskringkasting (Denmark broadcast co.) NRL Naval Research Laboratory (US) NRN National Radio News (Australia) NRO National Reconnaissance Office (operates US spy satellites) NRS (1)Naval Radio Section (Canforce) NRS (2)Nordic Radio Society NRT Navigation Response Team NRTF Naval Radio Transmitting Facility (US) NRV US Coast Guard COMMSTA, Guam, controlled from CAMSPAC NRWATS Naval Rotary Wing Aircraft Test Squadron NRZ Nonreturn to Zero NRZL Nonreturn To Zero Level NRZM Nonreturn To Zero Mark NRZS Nonreturn To Zero Space NS Node switch NS/EP National Security/ Emergency Preparedness NSA (1)National Security Agency (US intercept and crypto) NSA (2)No Such Agency (NSA used to "not exist") NSA (3)Never Say Anything (NSA secrecy policy) NSAP Network Service Address Point NSAWC Naval Strike and Air Weapons Center (replaces "Top Gun") NSAWC Navy Strike Aircraft Weapons Center NSE National Support Element NSF National Science Foundation (US) NSFNET National Science Foundation Network, old Internet backbone NSK Narrowband shift keying NSS Navigation Safety System NSSL National Severe Storms Laboratory (US) NSTAC National Security Telecommunications Advisory Committee (US) NSU Network Server Unit nT Nanotesla (unit of magnetic flux=1nWeber/m) NT Not Tested NTA (1)National Telecommunications Alliance (NCS) NTA (2)National telecom administration (ITU member bodies) NTC National Teleregistration Center (FEMA) NTCC Naval TeleCommunications Center NTCN National Telecommunication Coordination Network NTIA National Telecommunications and Information Administration NTM Notice to Mariners NTMS National Telecommunications Management Structure (national emergency plan) NTN NATO Track Number NTS (1)National Traffic System, amateur message network NTS (2)Naval Telecommunications System NTSC (1)National Television Standards Committee (US TV standard) NTSC (2)Never The Same Color (result of using above) NTT Nippon Telegraph and Telephone (Japanese "FCC") NUC Nuclear NUCINT Nuclear Intelligence NUCO Numerical Code (US Navy) NUDET Nuclear detonation NUKO Old group call: To All Ships Receiving MERCAST NUL Nothing (ASCII 0000) NVG Night-Vision Goggles NVIC Navigation & Vessel Inspection Circular NVIS Near Vertical Incidence Skywave NVOAD National Voluntary Organizations Active in Disaster NVRAM Nonvolatile Random Access Memory NW (1)CW brevity code: "Now," or "New" NW (2)Northwest NWC Naval Weapons Center NWCG National Wildfire Coordination Group NWEF Naval Weapons Evaluation Facility NWR NOAA Weather Radio NWS (1)National Weather Service (US) NWS (2)Naval Weapons Station NWSFO National Weather Service Forecsting Office NWSOP National Winter Storm Operation Plan nx News NYSEMO New York State Emergency Management Office O&O Owned & Operated (by broadcast network) o/l Online O/R On request O/R Address Originator/Recipient Address O/S Out of service OARNET Ohio Academic Resources Network OASD/C3I Office of the Assistant Secretary of Defense for command, control, communications and intelligence OASIS Operational and Supportability Implementation System (FAA) OBC On-board computer OBS Ship weather report in standard form OCA Oceanic Control Area OCC Operations Control Center (Centre) OCD (1)Office of Civilian Defense, obsolete OCD (2)Operations Control Division OCNL occasional OCONUS Outside Continental United States OCOT Office of the Chief of Transportation (US Army) OCR (1)Optical Character Recognition OCR (2)Optically Coupled Regenerative OCS Office of Coast Survey OD (1)Officer of the Day OD (2)Overdose OD (3)Outside Diameter ODBC Open DataBase Connectivity (Microsoft) ODMA Orthogonal Domain Multiple Access ODMP Orbiter Maintenance Down Period (NASA) OE Operating Expense OEI One Engine Inoperative OEM Original Equipment Manufacturer OFCM Office of the Federal Coordinator for Meteorology OFDM Orthogonal Frequency Division Multiplex OFP Operational Flight Program OG Operations Group OGA Other Governmental Agencies (formerly "NOC") OHD overhead OIC Officer In Charge OIS Organization for Internet Security OLAC Open Language Archives Community OLAP On-Line Analytical Processing OLF Outlying Landing Field (US Navy) OLTP On-Line Transaction Processing (IBM) OLX OLE Custom Control (MS made it up... i didn't) OM Male voice ("Old Man") OMAR French: Organisation MARitime des transmissions haute fréquence OMEGA Optimized Method for Estimated Guidance Accuracy (VLF Navigation) OMF (Weather) Observation Markup Format OMS ("ohms") Orbital Maneuvering System (NASA) OO Official Observer (Amateur) OOB (1)Out of band OOB (2)Out Of Bounds (classic Internet hack) OOC Official Observer Coordinator (Amateur) OOK On-off keying OOOI Out, Off, On, In (ACARS time reporting) OOP Object-Oriented Programming OOW Operations Other than War OP Observation Post op Operation OPAL Orbiting Picosat Automatic Launcher OPBAT (1)Operations, Bahamas and Turks (Old DEA) OPBAT (2)Operation Bahamas, Turks and Caicos (Newer) OPC (1)Ocean Prediction Center, Camp Springs, MD OPC (2)Operations Center OPCEN Operations Center OPCODE Operations code OPCON Operational control OPF Orbiter Processing Facility (NASA) OPLAN Operations plan OPORD Operation order OPSEC Operation Security OQPSK Offset Quadrature Phase Shift Keying OR Offroute (unscheduled flights, usually military) ORACLE Oak Ridge Automated Computer and Logical Engine ORBS Open Relay Behaviour-modification System (anti-email-spam) ORF Oesterreichischer Rundfunk (Austrian broadcasting co.) ORFM Office of Radio Frequency Management org organization (Internet) OS (1)Operating system (code that runs a computer) OS (2)Operations Support OS Operations Specialist (combines older USCG RD and TC) OS/2 Operating System 2, proprietary IBM op-system for PS/2 OS/2 Operating System II (IBM) OSACOM Operational Support Airlift Command OSC (1)Operations Systems Center, USCG, VA OSC (2)On-Scene Coordinator OSC (3)Oscillator [~] OSCAR Orbiting Satellite Carrying Amateur Radio OSCE Organization for Security and Cooperation in Europe OSCR Ocean Surface Current Radar OSEI Operational Significant Event Imagery (NOAA) OSI Open Systems Interconnection (coincidentally, OSI is by ISO) OSIR ISO's famous 7-layer "OSI Reference Model" for packet OSIRM ISO's famous 7-layer "OSI Reference Model" for packet OSPF Open Shortest Path First OSS Office of Special Services, WWII OSTP Office of Science and Technology Policy (US Government) OSWER Office of Solid Waste and Emergency Response OTAN NATO in French OTAR Over-The-Air Rekeying (crypto) OTASP Over-the-Air Service Provisioning (telco) OTCIXS Officer in Tactical Command Information Exchange System OTHB Over The Horizon Backscatter radar OTHR Over the horizon radar OUI Organizationally Unique Identifier Out Voice prosign: Contact completed, going back to listening OVC overcast Over Voice prosign: Transmission completed, go ahead OVR Overcast OWF Optimum Working Frequency, realtime version of FOT OWI Office of War Information, WW II OWVL One-Way Voice Link (example is "numbers") P greater than P Plus P Power (in watts) P/N Part number p/p (1)phone patch p/p (2)point-to-point p/p (3)peak-to-peak P25 (APCO) Project 25 (digital radio standard) PA (1)Power amplifier PA (2)Public address system PA (3)Passenger agent PA (4)Privacy Act PA (5)Proceed Authority PAC (1)Pacific PAC (2)Personnel and Administration Center PAC (3)Political Action Committee PAC-3 Patriot Advance Capability 3 PACAF Pacific Air Forces (US) PACAREA Pacific Area (USCG) PACMARF Pacific Military Altitude Reservation Function PACSAT Packet radio satellite PACTOR Packet teleprinting over radio (modes 1 and 2) PAD Packet assembler/disassembler PADAN PAcket Digital Amateur Network PADIL PATRIOT Digital Information Link (US missile batteries) PAEW Persons And Equipment Working PAL (1)Phase Alternating Line (W. Europe TV standard) PAL (2)Positive Arm Latches PAL Plus 16:9 PAL PAM (1)Phase-Amplitude Modulation, modems PAM (2)Pulse Amplitude Modulation PAM (3)Pluggable Authentication Modules (Linux) PAN Prosign: priority safety traffic follows (also "PAN PAN") [~] PANA Pan-African News Agency PANS Procedures for Air Navigation Services PAO Public affairs officer PAP (1)Polska Agencja Prasowa PAP (2)Password Authentication Protocol, computer networks PAPI Precision Approach Path Indicator PAR Precision Approach Radar, new name for GCA PARC Palo Alto Research Center (Xerox, obsolete) PASR personnel accounting and strength reporting PATRECONFOR Patrol and Reconnaissance Force (US Navy) PATWAS Pilot Automated Telephone Weather Answering Service PAVE Precision Acquisition Vehicle Entry PAVE PAWS Phased array SLBM warning system, 4 US Coastal sites PAWS (1)Phased Array Warning System, e.g., PAVE PAWS PAWS (2)Programmable Analyst Work Station PAWSS Ports and Waterways Safety System PAWSS Ports & Waterways Safety System PAX (1)Passengers PAX (2)~"Peace" in Latin ("Pax Americana") PBBS Packet Bulletin Board System PBN Performance Based Navigation PBS Public Broadcasting System PBT Portable Breathalyzer Test (police drunk testing) PBX Private Branch Exchange (telco) PC (1)Personal Computer PC (2)Printed Circuit PCI Peripheral Component Interconnect (Intel) PCM Pulse code modulation PCMCIA Personal Computer Memory Card International Association PCN Personal Communication Network PCS (1)Personal Communication Service (mobile phone) PCS (2)Performance Control System PCS (3)Prelaunch Compatibility Station (GPS) PCS (4)Personal Communications System PCSS Port & Coastal Security System PDA Personal Digital Assistant (palmtop computer) PDC (1)Pre-Departure Clearance PDC (2)Personal Digital Cellular PDF Portable Document Format (Adobe) PDM Pulse Duration Modulation PDP Programmed Data Processor (DEC, 1960 on, classic machines) PDS Particularly Dangerous Situation (NOAA/NWS) PDT Pacific Daylight Time, US PDU Protocol Data Unit PE (1)ice pellets PE (2)Portable Executable (Micky$oft) PEM Privacy Enhanced Mail PEO-C3S Program Executive Office - Command, Control and Communications Systems PEO-IEWS Program Executive Office - Intelligence, Electronic Warfare and Sensors PEP Peak envelope power PER Packed Encoding Rules PERL Practical Extraction and Report Language, Unix scripting pers personnel PERSCOM Personnel command PEST Plasma Experiment Satellite Test PETAL Preliminary Eurocontrol Trial Air-ground data Link pf Picofarad PF Pilot Flying PFC (1)Private, First Class PFC (2)Prepared Form Card, a homemade QSL for a station to sign PFRR Poker Flat Research Range, AK PGP Pretty Good Privacy, e-mail encryption program PHOTINT Photographic Intelligence (satellite pics, etc.) PHP PHP Hypertext Processor (a recursive acronym) PI protection interval PIC Programmable Interrupt Controller (computers) PIN Personal Identification Number pine Pine Is Nearly/Not/Not yet Elm, Unix mailer PING Packet InterNet Groper (ICMP "ping pong" tester for net) PIO (1)Public Information Officer PIO (2)Programmed Input/Output PIP Peripheral Interchange Program, old CP/M copy PIPEX Public IP EXchange (UK) PIREP Pilot Report, weather in standard form PIW Person(s) In Water PK WND peak wind PKW (1)German: Personenkraftwagen (passenger car) PKW (2)Polish: Polski Kontyngent Wojskowy (Polish Military Contingent, in KFOR) PL (1)"Private Line," Motorola tradename for CTCSS PL (2)Pilot light PL/1 Programming Language 1 (computer code) PLB Personal Locator Beacon PLC Power Line Carrier (Power company LF control system) PLIP Parallel Line Internet Protocol PLL (1)Phase Locked Loop PLL (2)prescribed load list PLS CW brevity: Please [~] PLT Power Line Telemetry PM (1)Phase Modulation, slightly resembles FM PM (2)Post Meridian, hours between noon and 11:59 local PM (3)Project Manager PMBO Participating Mailbox PMC Personnel management center PMCS Preventive maintenance checks and services PME Protective Multiple Earth (ground) PMFC Pacific Missile Firing Center PMO Provost Marshall's Office PMR (1)Professional Mobile Radio (Europe) PMR (2)Private Mobile Radio (UK) PMRS Private Mobile Radio Service PMSV Pilot-to-Metro Service PM-TRCS Project manager, tactical radio communication systems PN Pseudo-Noise PNA Philippines News Agency PNF Pilot Not Flying PNO precipitation amount not available PnP Plug and Play PNP Positive/Negative/Positive; transistor type PO dust/sand whirls (dust devils) POB Persons On Board POC Point of Contact POCSAG Post Office Code Standardization Advisory Group (paging) POD Point of debarkation POE Point of embarkation POES Polar Orbit Environmental Satellite POETS Push Off Early - Tomorrow's Saturday POL Petroleum, oils, and lubricants POL-ARQ Polish diplomatic ARQ teleprinter system POP (1)Post Office Protocol (Internet) POP (2)Point of presence POP (3)Probability Of Precipitation (NOAA) POR Pacific Ocean Region (USCG) PORTS Physical Oceanographic Real-Time Systems POSIX OSI standard, like Unix POSIX Portable Operating System Interface POST Power-On Self Test pot Potentiometer [~] POTS (1)Plain Old Telephone System POTS (2)Plain Old Telephone Service POTS (3)Purchase Of Telephone Service (US Government) POTUS President Of The United States pp Phone patch PP Transmission is in Portuguese PPDL Point to Point Data Link PPE Personal Protective Equipment PPM (1)portable pixmap PPM (2)Page per minute PPM (3)Parts per million PPM (4)Pulse Position Modulation PPP Point-to-Point Protocol PPPoE Point-to-Point Protocol over Ethernet PPR Prior Permission Required (military landing permit) PPTP Point-to-Point-Tunneling Protocol PQM path quality matrix PR (1)Puerto Rico PR (2)Person Reporting (police) PR partial PRB Personal Radio Bureau (FCC) PRB-1 Personal Radio Bureau 1, FCC resolution attempting to preempt local radio laws PRC (1)Pseudo-Range Correction (DGPS) PRC (2)People's Republic of China prep preparation PRESRR pressure rising rapidly PRFG partial fog PRM (1)Pulse rate modulation PRM (2)Precision Runway Monitor PRML Partial Response Maximum Likelihood (HD transfer mode) PROM Programmable Read Only Memory ProSEDS Propulsive Small Expendable Deployer System (NASA) Prosign Procedural Signal ("over," etc.) PRZ Polar Return to Zero PS/2 Personal System 2, IBM's less-than-sensational replacement for the PC PSA Public Service Announcement PSAP Public Safety Answering Point PSB Personnel services battalion PSDN Public Switched Data Network PSE CW brevity: Please PSK (1)Phase-shift keying PSK (2)Pre-Shared Key (Wi-Fi) PSK-31 Phase-shift keyed very narrowband simplex direct printing scheme PSL Process Specification language PSM Pulse step modulation PSO Public service officer PSR Primary Surveillance Radar PSRAM Pseudo Static Random Access Memory, obsolescent PSS (1)Personnel service support PSS (2)Packet Switch Stream (British Telecom) PSSN pseudo sunspot number PST Pacific Standard Time, US PSTN Public Switched Telephone Network PSWAC Public Safety Wireless Advisory Committee PT (1)Preparedness, Training and Exercises Directorate (FEMA) PT (2)Patrol Torpedo (boat) PT (3)Permeability Tuned PTC Parallel Test Component (Linux) PTD Pilot-to-dispatcher PTO Permeability tuned oscillator PTR (1)Primary Training Range PTR (2)Puerto Rico PTR (3)Pointer [~] PTT (1)Push to talk PTT (2)Post, Telegraph and Telephone administration (UK) PU ("Papa Uniform") participating unit pub publication PUP Principal User Processor PVA Positive Vorticity Advection (wx geeks) PVASI Pulsating Visual Approach Slope Indicator PVO private volunteer organization PWINO precipitation identifier sensor not available PWM Pulse width modulation PWR Power PY spray Q HectoPascals (U.S. METAR variant) Q Quality (measure of selectivity in inductive circuits) QA Quality Assurance QAM Quadrature Amplitude Modulation QCWA Quarter Century Wireless Association (amateur) QLF Facetious prosign: Now send with your LEFT foot QNH Set your altimeter to -- barometric pressure QoS Quality of Service QPC Question Pool Committee (amateur exams) QPF Quantitive Precipitation Forecast (NOAA) QPSK Quaternary Phase Shift Keying QRA The name of my station is -- QRCT Quick Reaction Communications Terminal QRG (1)Your frequency is -- kHz QRG (2)The frequency is --, Kenneth QRH Drift ("Your frequency varies...") QRL I'm busy; frequency is in use QRL? (1)Are you busy? QRL? (2)Is this frequency in use? QRM Interference QRN Noise QRO (1)High power operation QRO (2)Please increase power QRP (1)Low power operation QRP (2)Please reduce power QRP (3)Quick Reaction Package (US Army vehicle) QRQ Please increase code sending speed QRR Old land distress call, now SOS, MAYDAY, or QRRR QRRR Old land distress call QRS Please reduce transmission speed QRSS (1)VERY low speed CW ("super QRS") QRSS (2)Quasi-Random Signal Source QRT (1)Station has ceased transmitting QRT (2)Please cease transmitting QRU I have no traffic for you QRU? Do you have traffic for me? QRV I am ready (go with your traffic) QRX Please standby QSA Signal strength QSB Fading QSD Your keying is defective QSK Duplex CW ("break-in") QSL (1)A card or letter confirming reception of a radio station QSL (2)Acknowledgment of transmission, a fancy "roger" QSO Communications between two or more stations QST (1)General call: "Hello all amateurs" QST (2)Ham radio magazine published by ARRL QSTAG Qadripartite Standardization Agreement QSV Send Vs QSV? Should I send Vs? QSX I am listening on... QSY (1) Frequency change QSY (2) Change frequency to -- kHz QTC Message QTH Location of station QWD Quarterly World Days, observation intervals QWERTY Name of standard typewriter keyboard, from top row of ltrs QWZ Facetious prosign: Are you woozy? I am woozy R (1)CW prosign: "Message received" R (2)DC resistance (in ohms) R (3)Resistor R (4)Right R (5)Runway R chks Radio checks R&D Research & Development R&O Report & Order (FCC) R/T Receiver/Transmitter R/W Rotary wing (helicopter) R3E Single sideband, reduced carrier (usually 6 dB) radiotelephony RA (1)Radio Authority (UK) RA (2)Rain RA (3)Radio Australia RA (4)File format: Real Audio RAA Royal Australian Army RAAF Royal Australian Air Force RAC-ARQ ARQ mode propietary to Racal/Thales RACES Radio Amateur Civil Emergency Service, FEMA affiliates Racon Radar Beacon RAD Radiological [~] Radar Radio Detection And Ranging RADARA Regional And Domestic Air Route Area RADAY Radio Day (US Mil) RADIL ROCC/AWACS digital information link RADINT (1)Radar intelligence RADINT (2)Radiation intelligence RADIUS Remote Authentication Dial In User Service RADM Rear Admiral RADMO Radio Mode RADSL Rate Adaptive Asymmetric Digital Subscriber Line RADSTA Radio Station RAF Royal Air Force RAG Replacement Air Group RAI Radio Televisione Italiana RAID (1)Redundant Array of Inexpensive Disks (servers) RAID (2)Rapid Assessment and Initial Detection team (FEMA/Army NG) RAIL Runway Alignment Indicator Lights RAIM Receiver Autonomous Integrity Monitoring RAM Random Access Memory (can be changed) RAMAC Random Access Method Of Accounting And Control (IBM, 1956) RAMDAC Random Access Memory Digital to Analog Converter RAMP Radar Modernization Project RAN Royal Australian Navy RAOC rear area operations center RAP RAPid Refresh Model (wx) RAPCON Radar approach control RARP Reverse Address Resolution Protocol RAS Remote Access Server RASC Radio Atmospheric Science Center (Japan) RASP Radio Science And Propagation RATCF Radar Air Traffic Control Facility (USN) RATS Radio Amateur Telecommunications Society RATT Radioteletype (usually military 75/100 bd) RAV Restricted Availability RAVEC Radar Vector RB Radar Beacon RBL Realtime Blackhole List (Internet) RBL Realtime Blackhole List (spam filtering) RBS Radar Bomb Scoring RC (1)Reserve Components (US Army) RC (2)Radio control RCA Radio Corporation of America RCC (1)Rescue Coordination Center (GMDSS) RCC (2)Range control center (USAF) RCC (3)Resource control complex RCC (4)Rag Chewer's Club (ham award) RCCC Range communications control center RCDS Raster Chart Display System RCI Radio Canada International RCIED Remote Controlled Improvised Explosive Device RCMA Dead scanner radio club, which included HF utility RCNC Range communications network controller RCNY Rules of the City of New York RCO Range Control Officer rcp Remote Copy (unix) RCP Resource Change Proposal RCR Runway Condition Reading RCS (1)Radio Communication System RCS (2)Reaction Control System (NASA) RCS (3)Radar cross-section RCS (4)Radio Conference Subcommittee (of IRAC) RCS (5)Remote Control System RCS Radio Conference Subcommittee rcv Receive mode rcvr receiver RD (1)replacement directorate RD (2)Restricted data RD (3)Regional Director RD Radar man (old USCG grade) RDARA Regional and Domestic Air Route Area RDEC Research, Development and Engineering Center (Army) RDF (1)Radio direction finding RDF (2)Resource Description Framework RDF (3)Resource Description Format RDF (4)Rapid Deployment Force RDF (5)Repeater Distribution Frame (telephony) RDF (6)Raw Data File RDF (7)Record Description Field RDFT Redundant Digital File Transfer (used by HM01) RDM (1)Radio Data Modem RDM (2)Radio Diffusion Marocaine (Morroco) RDNS Reverse Domain Name System lookup (Internet) RDRAM RAMBUS (company) Dynamic Random Access Memory RDS Remote Data Service RDT Remote digital terminal RE Reverse engineering REACT Radio Emergency Associated Communication Team, like ARES, but on CB and GMRS REC Radio-electronic combat rec receive recon reconnaissance REDHORSE Rapid Engineer Deployable Heavy Operational Repair Squadron, Engineer REE Radio Exterior de Espana (Spain overseas broadcaster) Reg regulation, includes radio rules REJ Packet control frame: Reject, data out of sequence Rem (1)Remark (computer programming) Rem (2)Radiation-equivalent, man (nuclear safety) REMES Reference Message REP Radiological Emergency Preparedness (program) REQ request req'd required RES Radio Equipment and Systems RETMA Radio, Electronics, Television Manufacturers Assn, now EIA retrans retransmission rev reverse RF Radio Frequency RF/EMPINT Radio Frequency/Electromagnetic Pulse Intelligence RFC (1)RF Choke RFC (2)Request For Comment (Internet standards) RFDS Royal Flying Doctor Service (Australia) RFDU RF distribution unit RFE Radio Free Europe RFI (1)RF Interference RFI (2)Radio France International RFID Radio Frequency Identification RFP Request For Proposals RFPI Radio For Peace International, Costa Rica RFR RF radiation RG-# Radio Guide, Radio Group, Radio Grade (differs) - coax cable designator RGB Red, Green, Blue; additive color mixing like TV RGS Remote ground station RH Relative Humidity RHC Radio Havana Cuba RHCP Right-hand circular polarization RHOJ Radar home on jam RI (1)Routing indicator (Telex or radiograms) RI (2)Ring Indicator (modem line) RIAA Recording Industry Assn of America (audio) RIFF Resource Interchange File Format (Microsoft MIDI) RIMM (1)RAMBUS In-Line Memory Module RIMM (2)Removable Interchangeable Media Module RIO (1)Radar Intercept Officer RIO (2)Relative Ionospheric Opacity Riometer Relative Ionospheric Opacity Meter (uses cosmic RF) RIPE Regional Internet Registry for Europe RIPE Reseaux IP Europeens (Internet registry) RISC Reduced Instruction Set Computing, chip architecture RIT Receiver Incremental Tuning, same as "clarifier" RITL Radio In The Loop (telephony) RJ Radio Japan RLC Resistance-Inductance-Capacitance (network) Rlogin Remote Login, networking program like telnet RM (1)("Romeo Mike") Radioman, radio operator RM (2)Radio Man (old USCG grade, became TC) RM (3)File extension: Real Media RMA (1)Revolution in Military Affairs (US tax subsidized paper crunching) RMA (2)Return Merchandise Authorization RMA (3)Reduced Major Axis) RMA (4)Old Microsoft midi file format (see MIDI) RMC Regional Meteorological Center RMI (1)Radio Magnetic Indicator RMI (2)Republic of the Marshall Islands RMI (3)RIFF MIDI (an acronym made up of acronyms) RMI (4)Radio Miami International RMK Remarks RMP (1)Radio Mobile Patrol (NYPD car) RMP (2)Radio Motor Patrol RMP (3)Radio Móvil Privada (Spanish: Private Mobile Radio) RMP (4)Raster Map Product RMP (5)Radio Merkury Poznan (Poland) RMS (1)Royal Majesty Ship RMS (2)Royal Mail Steamer (obsolete?) RMS (3)Root Mean Square RMS (4)Remote Mine Sweeping RMS (5)Radar Manual Systems RMS (6)Remote Manipulator System (space shuttle's robot arm) RMTN Region IV Meteorological Telecommunication Network RN (1)Radio Netherlands RN (2)Royal Navy RN (3)Registered Nurse RN (4)Revision Notice RN Radio Netherlands rn Read News, usually the default Unix Usenet reader RNAV Area Navigation (IFR flight) RNDZ Rendezvous RNP Required Navigation Performance RNP/AR Required Navigation Performance Authorization Required RNR Packet control frame: Receive Not Ready RNZ Radio New Zealand RNZAF Royal New Zealand Air Force RNZI Radio New Zealand International RNZN Royal New Zealand Navy RO (1)Radio Officer (traditionally trained in Morse code) RO (2)Receive Only ROA Remotely Operated Aircraft ROC (1)Regional Operating Center (FEMA/NCS) ROC (2)Rear operations center ROC (3)Reservoir Operating Center (USACE) ROCC Regional Operations Control Center ROE Rules Of Engagement ROFL Rolling On Floor Laughing (Internet, also ROTFL) ROFOR Route Forecast Roger Voice Prosign: Message Received (from "R" in Morse code) ROLAP relational on-line analytical processing (databases) ROM Read Only Memory (can't easily be changed) ROMES Refrence Our Message ROMPRES Romanian press agency RON Remain Over Night (US military) ROSE RATS Open System Environment (Packet; see RATS) ROTATE Radar Observations of Tornadoes And Thunderstorms Experiment ROTFL Rolling On The Floor Laughing (Internet, also ROFL) ROTHR Relocatable (HF) Over-The-Horizon Radar ROTR Receive-Only Typing Reperforator (tape printer) ROU-FEC Romanian FEC ROVER Remote Out-of-Vehicle Emergency Radio (LAPD) RP (1)Received Pronunciation (British radio "accent") RP (2)Reporting Party (Police) RPA (1)Remote Passphrase Authentication RPA (2)Radio-Programming Application RPC Remote Procedure Call (lousy Windoze security) RPG Report Program Generator (strange IBM computer language) RPI Runway Point of Intercept RPM Red (Hat) Package Manager (Linux) rpm Rotations per minute RPN Reverse Polish Notation (computing) rpt (1) Reception report rpt (2) CW prosign: repeat Rptr Repeater RPU Remote Pickup Unit RQ (1)Repeat Request RQ (2)Request acknowledgment of receipt (DSC protocol) RQS Request to send (modem handshaking line, rare name for RTS) RR (1)Transmission is in Russian RR (2)Radio Regulation (ITU) RR (3)Railroad (don't laugh, some use HF) RR (4)Packet control frame: Receive Ready RR (5)Response and Recovery Directorate (FEMA) RR (6)Radio Reloj (clock radio, SS news format) RRC (1)Regional Radio Conference (ITU) RRC (2)Range Rate Correction (DGPS) RRP Runway Reference Point RRSS Radparker Relay Spam Stopper RRx Routine Report, where x is a sequential letter, used for delayed METAR RS (01)radiated susceptibility RS (02)range squadron RS (03)reentry system RS (04)requirements submission RS (05)resource scheduling RS (06)Radio Satellite (Russian amateur) RS (07)EIA Recommended Standard, RS-232 was one RS (08)Record Separator (ASCII) RS (09)Radio Sweden RS (10)Reference Station RS-232 Recommended Standard 232, standard serial I/O, now EI-232 RSA (1) Rivest-Shamir-Adelman, inventors of a proprietary type of public-key encryption RSA (2)Republic of South Africa RSGB Radio Society of Great Britain rsh Restricted shell (Unix) RSN Real Soon Now (when everything is going to happen) RSO Range Safety Officer RSOC Regional SIGINT Operation Center (like Menwith, UK) RSS (1)Really Simple Syndication (world wide web) RSS (2)Radio Subsystem RSS (3)RDF Site Summary (see RDF #2) RSS (4)Rich Site Summary RST (1)Signal report: Readability, Strength, [Tone] (if CW) RST (2)Reset RSTA reconnaissance, surveillance and target acquisition RSVP (1)Resource Reservation Protocol RSVP (2)Repondez Si'Vous Plait (Please Respond, party invitations) RT (1)Radiotelephone RT (2)Receiver-transmitter RT (3)Receive Timing RT (4)routing table RTB Return to base RTC (1)Rail Traffic Control RTC (2)Remote Type Certification RTCA Radio Technical Commission for Aeronautics RTCE Reat-Time Channel Evaluation RTCM Radio Technical Commission for Maritime (services) RTCP Real Time Control Protocol RTD Return to duty RTDC Real time data controller RTE Radio Telefs Éireann (Ireland) RTF (1)Radiodiffusion Television Francais RTF (2)Runtime file RTFM Read the [fine] manual RTFMS Real-Time (HF) Frequency Management Software RTHK Radio Television Hong Kong RTLS (1)Return to launch site RTLS (2)Real-Time Locating Systems RTO (1)Responsible Test Organization (US) RTO (2)Radiotelephone Operator (LAPD) RTO (3)Range training officer RTOK Retest OK RTOS Real Time Operating System RTS Request To Send (secondary handshaking modem line) RTT (1)Radioteletype RTT (2)Radio Transmission Technology RTTY Radioteletype RTZ Return To Zero R-UIM Removable User Identity Module RUMES Reference Your Message RVR Runway Visual Range RVRNO RVR system not available RVSM Reduced Vertical Separation Minimum RWI radio wire integration (changed to NRI-net radio interface) RWR Radar Warning Receiver RWY runway RX (1)Receiver RX (2)Religious programming RX (3)Retransmission RXD Received Data (Serial I/O) RXR Receive Reversed (usually RTTY Mark/Space) RY RYRYRY teleprinter test call RZ Return to Zero RZL Return to Zero Level S (1)south S (2)Siemen s second S&TCD Space and Terrestrial Communications Directorate s/n Serial number S/N Signal/Noise ratio S/NR Signal/Noise Ratio s/off Sign off s/on Sign on s/w software (computer programs and instructions) S1 Adjutant (US Army) S2 Intelligence Officer (US Army) S3 Operations and Training Officer (US Army) S3A Supervised Standard Scientific Analysis S4 Supply Officer (US Army) SA (1)South Atlantic SA (2)Sand SA (3)Situational Awareness SA (4)Selective Activation (GPS) SAA South Atlantic Anomaly, a large magnetic deviation SAAF Small Austere Air Field SAAFR Standard use Army Aircraft Flight Route SABC South African Broadcasting Corporation SABM Packet control frame: Set Async Balanced Mode (connect) SAC Strategic Air Command, now part of US Stratcom SACCS Strategic Automated Command & Control System SACD Super Audio Compact Disk (Sony/Philips) SACEUR Supreme Allied Command(er) Europe SACLANT Supreme Allied Commander, Atlantic {NATO} SAE Self Addressed Envelope (usually with IRC or "green stamp") SAFE Selected Area For Evasion SAGE Semi-Automated Ground Environment (early, huge, USAF system) SAID Sub-Auroral Ion Drift SALS Short Approach Lighting System SAM (1)Special Air Mission (US Air Force VIP flight) SAM (2)South America (MWARA) SAM (3)Surface-to-Air missile SAMCOM Special Air Missions Communications ("Mystic Star") SAME Specific Area Message Encoding (US weather warnings) SANA Syrian Arab News Agency SAO (1)South Atlantic Ocean SAO (2)Surface Aviation Observation (weather) SAP (1)Second Audio Program SAP (2)Special-Access Program SAP (3)Soon As Possible, when every radio project has to be done SAR (1)Search and rescue SAR (2)Synthetic Aperture Radar SAR (3)Station Availability Report (SHARES) SARAH Standard Automated Remote to Autodin Host SAREX Shuttle Amateur Radio Experiment, obsolete SARNET NOAA SARSAT Network SAROPS Search & Rescue Optimal Planning System SARPs Standards and Recommended Practices SARSAT Search And Rescue Satellite SART (1) Survival Craft Radar Transponder SART (2) Search And Rescue Transponder SARTG Scandinavian Amateur Radio Teleprinter Group SASE Self Addressed Stamped Envelope SASP Separation and Airspace Safety Panel SAT (1)South Atlantic (MWARA) SAT (2)Satellite SAT (3)Saturday SATAN Security Administrator Tool for Analyzing Networks SATCOM Satellite communication SATERN Salvation Army Team Emergency Radio Network SAVASI Simplified Abbreviated Visual Approach Slope Indicator SAWS Stand Alone Weather System SB (1)Standby (EIA-449) SB (2)Sierra Bravo, son of a [female dog] SB (3)Sideband SBA (1)Sovereign Base Area SBA (2)Small Business Administration S-band 1.55-5.2 Ghz microwave band SBAS (1)Space Based Augmentation System SBAS (2)Satellite Based Augmentation System SBCS Single Byte Character Set SBD Safe Braking Distance (railroad) SBD1 Safe Braking Distance + 1 minute (also SBD2, etc) SBE Society of Broadcast Engineers SBS-1 Mode-S receiver by Kinetic Avionics SC (1)Sudden commencement (of a magnetic storm; causes fadeouts) SC (2)Selective Calling SC-104 Special Committee #104 (DGPS Standard) SCA (1)Subsidiary Communications Authorization (US commercial FM) SCA (2)Shuttle Carrier Aircraft (NASA's modified 747 for transporting orbiter) SCADA Supervisory Control and Data Acquisition System SCAMP Single-Channel Antijam Man-Portable SCAT Strategic Communications (Continuing) Assessment Program SCBA Self-Contained Breathing Apparatus SCCS satellite communications control system SCDCC Southern California Digital Communications Council (Amateur) SCDX Sweden Calling DXers SCDXC Southern California DX Club SCI San Clemente Island (USN, CA) SCMA Southern California Monitoring Association SCN (1)System Coordination Net (US Coast Guard) SCN (2)SHARES Coordination Net (US NCS/SHARES) SCO (1)Subcarrier oscillator SCO (2)Santa Cruz Organization, a software source SCO (3)State Coordinating Officer (FEMA/NSEP) SCOPE System Capable Of Planned Expansion (Scope Command) SCP Southern Command Post, US Army, Camp Bondsteel, Kosovo SCPC Single channel per carrier SCPT Single channel per transponder SCPTOC Southern Command Post Tactical Operations Center, Kosovo SCR Silicon controlled rectifier SCRAM Scramble; automated fast shutdown of nuclear reactor [~] SCRRBA Southern California Repeater/Remote Base Assn (Amateur) SCS Satellite Control Squadron SCSI Small Computer System Interface ("scuzzy") SCSL stratocumulus standing lenticular cloud SCT Scattered clouds SCTP Stream Control Transmission Protocol SDARS Satellite Digital Audio Radio Service (Sirius & XM) SDF Simplified Directional Facility SDH Synchronous Digital Hierarchy SDI Strategic Defense Initiative, U.S. space money sink SDLC Synchronous Data Link Control, bitwise computer comm protocol SDLP Station Data Link Protocol SDM Short Data Message SDNRIU Secure Digital Net Radio Interface Unit SDR Software Defined Radio SDRAM Synchronous Dynamic Random Access Memory SDSL Symmetric Digital Subscriber Line SDTV Standard Definition Television SDU Secure data unit SDX Semi-duplex SE Southeast SEA Southeast Asia (MWARA) SEAD Suppression of Enemy Air Defenses SEAL Sea, Air, Land (US Navy special op teams) SEAM Space Emergency Action Message SEATO South East Asia Treaty Organization (now ASEAN) sec Second SEC Software Engineering Center (Army) SECAF Secretary of the Air Force SECAM (1)SEquentiel Couleur A Memoire, weird French TV standard, adopted by Russian bloc to keep out Western TV SECAM (2)Simply Everything Contrary to America SECDEF Secretary of Defense (US) SECT SHARES Emergency Coordination Team SECURE State Emergency Capability Using Radio Effectively SECURITE Prosign: safety traffic follows; uses FF pronunciation SEE-CURE-EE-TAY SEDENA Secretaria de la Defensa Nacional (Mexico) SEE Stimulated Electromagnetic Emissions SELCAL Selective Calling (tones or numbers) [~] SELFEC Selective FEC SELSCAN Proprietary name for Collins scanning ALE HF radio system SENS System Event Notification Service (Windows) SENSAPI System Event Notification Service API (nested acronym) SENSE Synthetic Environments for National Security Estimates SEP Solar Energetic Particle Event (observation interval) SES Ship Earth Station SESAR Single European Sky ATM Research SESC Space Environmental Services Center SESEF Ship Electronic Systems Evaluation Facility (US Navy) SETI Search for Extra-Terrestrial Intelligence (by radio) SEVOCOM Secure voice communications SEW Space & Electronic Warfare SF Special Facility SFA Single Frequency Approach SFC surface SFCG Space Frequency Coordination Group SFDU Standard formatted data unit SFF Small Form Factor (hard disks) SFU Solar flux unit SG Signal ground SG snow grains SGIN Subgroup Identification Number (FCC) SGML (1)Standard Generalised Markup Language SGML (2)Standard Generalized Markup Language SGRAM Synchronous Graphic Random Access Memory SGT Sergeant SH (Rain) Showers sh Bourne Shell, originally the Unix default command interpreter SHA-1 Secure Hash Algorithm-1, US code SHAEF Supreme Headquarters, Allied Expeditionary Forces SHAPE Supreme Headquarters, Allied Powers, Europe SHARES SHAred RESources, transferred to DHS SHF super high frequency SHIFOR Stastical Hurricane Intensity FORecast SHIPS Stastical Hurricane Intensity Prediction Scheme SHOALS Scanning Hydrographic Operational Airborne LIDAR Survey SHTTP Secure Hypertext Transfer Protocol (web) SI (1)Systeme Internationale d'Unites; a standard unit system SI (2)Shift In (Baudot & ASCII) SIC (1)Service Identification Code SIC (2)Standard Industrial Classifification SIC (3)Standards Implementation Committee SIC (4)Specific Inductive Capacity SID (1)Sudden Ionospheric Disturbance (solar flare effect) SID (2)Standard Instrument Departure SIG (1)Signature [~] SIG (2)Special Interest Group SIGCEN signal center [~] SIGINT Signals Intelligence [~] SIGMET Significant Meteorological warning signals [~] SILENCE MAYDAY Voice prosign: frequency is on standby for distress traffic; uses FF pronunciation SEE-LONCE MAY-DAY SIM (Card) Subscriber Identity Module SIMM Single In-line Memory Module SIMMS Single In-line Modular Memory System SIMOP Simultaneous Operation (of radios; an interference standard) Simul Simulcast SINAD Signal-plus-noise-plus-distortion to noise-plus-distortion ratio SINCGARS Single-Channel Ground/Airborne Radio System SINPFEMO Signal report: adds modulation and propagation details SINPO Signal report: adds Noise, Propagation to SIO SINS Ship's Inertial Navigation System SIO (1)Signal report: Strength, Interference, Overall (1-5) SIO (2)Serial Input/Output SIOP Single Integrated Operational Plan SIOPS Special Intelligence Operations SIPRNET Secure IP Router Network (military's own Internet w/NIPRNET) SIR Subsurface Interface Radar SIRTF Space Infrared Telescope Facility (NASA) SIS (1)Secret Intelligence Service (aka MI6, UK) SIS (2)Scramble Information Service (Dutch planespotter network) SITFAA Inter-American Air Forces Telecommunications Network (Spanish) SITOR (1) Simplex Teleprinting Over Radio SITOR (2) Simplex Telex Over Radio SITOR-A Simplex teleprinting over radio system, mode A (ARQ) SITOR-B Simplex teleprinting over radio system, mode B (FEC) SITREP Situation report SITSTAT Situation status SIU Server Interface Unit SJA Staff judge advocate SK CW prosign: "End of transmission," usually written VA SKC Sky clear SKYWARN NWS/ARRL amateur severe weather spotting network SLAM Standoff Land Attack Missile SLB Single Letter Beacon (Russian Navy marker xmsn) SLBM Sea-Launched Ballistic Missile SLC Space Launch Complex SLDMB Self-Locating Data Marker Buoy SLEP Service Life Extension Program SLEW Single-tone Link Eleven Waveform (NATO) SLHFB Single-Letter High-Frequency beacon (see SLB) SLIP Serial-Line Internet Protocol, older than PPP SLOC Sea lines of communication SLOSH Sea, Lake, and Overland Surges for Hurricanes (Model) SLP (1)Seaward Launch Point SLP (2)sea-level pressure SLPNO sea-level pressure not available SLR Shielded Loop Receiver SLS Space Launch Squadron SM Statute Miles SMART (1)Self Monitoring Analysis and Reporting Technology SMART (2)Self-Managed Arrival Resequencing Tool SMART (3)Segmented Method for Analytical Ray-Tracing SMART-T Secure Mobile Antijam Reliable Tactical Terminal SMASH Synchronous Multi-channel Access Signalling for HF SMB Server Message Block (Windows) SMC Space and Missile Center SMCC Strategic Mobile Command Center SMEX Small Explorer (Goddard/NASA) SMF Special Message Field SMH Shaking My Head (Internet) SMMW Sub-millimeter wave SMR Surface Movement Radar SMRS Specialized Mobile Radio System SMS Short Message Service ("texting") SMSI Sommet Mondial sur la Société de l'Information SMT Surface mount technology SMTP Simple Mail Transfer Protocol (Internet) SN (1)Serial number SN (2)Snow SNA System Network Architecture SNAFU Situation Normal All [Fouled] Up SNINCR snow increasing rapidly SNMP Simple Network Management Protocol, computers SNR Signal to Noise Ratio SNSM Société Nationale de Sauvetage en Mer (French National Society for Ocean Rescue) SO (1)Sheriff's Office SO (2)Shift Out (ASCII) SO DIMM Small Outline Dual Inline Memory Module SOA School Of the Americas (now WHISC) SOAP Simple Object Access Protocol (Internet) SOAR Special Operations Air Regiment SOB Souls On Board, number of people on an aircraft SOCOM Special Operations Command (US Navy) SODIMM Small Outline Dual In-line Memory Module SOF (1)Special Operations Forces SOF (2)Safety Of Flight SOH Start Of Heading (ASCII) SOHFRAD Special Operations High Frequency Radio SOHO (1)Solar Heliospheric Observatory (satellite at Lagrange point) SOHO (2)Small Office/Home Office (computing) SOI (1)Signal of interest SOI (2)Signal operation instructions SOI (3)Space Object Identification (NORAD) SOIR Simultaneous Operations on Intersecting Runways SOJ Small Outline J-lead SOL [Spit] Out of Luck SOLAS Safety Of Life At Sea (series of international treaties) Sonar Sound detection & ranging SONATRACH Société Nationale pour la Recherche, la Production, le Transport, la Transformation, et la Commercialisation des Hydrocarbures (Algerian national oil company) SONET Bell spec for data transmission over optical fiber SONGS San Onofre Nuclear Generating Station SOP Standing/Standard operating procedure SOPS Space Operations Squadron SOS Morse distress call, sent as one long character, replaced CQD [~] SOSB special operations support battalion SOSEC Surveillance Observation Satellite Evaluation Center SOSEX SOSUS Exercise SOSS (1)Sound Search Stations SOSS (2)Soviet Ocean Surveillance System SOSUS (1)Sound Surveillance Underwater System; network of hydrophones across Bering Straight to listen for Russian subs SOTDMA Self-Organizing Time Division Multiple Access SOUTHCOM Southern Command SOW (1)Start Of Watch SOW (2)Statement Of Work SP (1)South Pacific (MWARA) SP (2)Silent Period (500 kHz CW watch, obsolete) SP (3)Shore Patrol (US Navy MPs) SP (4)Space (RTTY) SPAC Spectrum Planning and Policy Advisory Committee SPACECOM US Space Command SPAR (1)Special Air Resources, US Air Force VIP flight SPAR (2)Seagoing Platform for Acoustic Research SPC Storm Prediction Center (NOAA) SPDT Single-Pole, Double-Throw SPDU HFDL: Squitter Protocol Data Unit SPE Satellite Proton Event; solar-terrestrial disturbance SPECI (1)Aviation Selected Special Weather Report, from French SPECI (2)an unscheduled report taken when certain criteria have been met SPEEDX Society for the Preservation of the Engrossing Enjoyment of DXing. I believe that an old "bug" key had this tradename as well. SPF Shortest Path First SPI (1)Service Provider Interface SPI (2)Stateful Packet Inspection SPINCOM Special Intelligence Communications Spkr Speaker SPL Sound Pressure Level SPL/1 High-Order Signal Processing Language #1 SPO Security, plans, and operations SPOD Seaport of debarkation SPR Safety and Performance Requirements SPS (1)Spectrum Planning Subcommittee (of IRAC) SPS (2)Standard Positioning Service SPS (3)Service Propulsion System (Apollo project) SPSS Space Surveillance Squadron SPST Single-Pole, Single-Throw Spt Support SPTT Security Policy Translation Table SPX Sequenced Packet Exchange SQ squalls sqdn Squadron SQL Structured Query Language (computer databases) SQPSK Staggered Quadrature Phase Shift Keying (like OQPSK) SR Special Reconnaissance (SR-71 "Blackbird") SRA Specialized repair activity SRAM Static Random Access Memory SRB Solid-Rocket Booster(s), NASA Space Shuttle, recovered by BRV SRMS Smart Resource Management System SRWBR Short Range Wide Band Radio SS (1)Transmission is in Spanish SS (2)Sandstorm SS (3)Shifting Standards (computer marketing technique) SS (4)Steam Ship SSA Supply support activity SSB Single Sideband SSC Sudden Storm Commencement (geophysics) SSD Satellite Services Division (NOAA) SSE South-southeast SSEC Selective Sequence Electronic Calculator (IBM, 1948) SSE-CMM Systems Security Engineering-Capability Maturity Model SSF Southern Straits of Florida SSG The Space Systems Group ssh Secure Shell (Unix) SSI Server Side Includes (web) SSI Space Science Institute SSID (1)Secondary Station Identifier (packet) SSID (2)Service Set Identifier (wireless networking) SSL Secure Sockets Layer (encrypted TCP/IP computer networking) SSN (1)Sunspot Number SSN (2)Nuclear Submarine (US Navy) SSN (3)Social Security Number (same as TIN - FCC forms) SSOM Spanish language numbers transmission, male voice SSPAR Solid State Power Amplifier-Receiver SSR (1)Secondary Surveillance Radar SSR (2)Soviet Socialist Republic (obsolete) SSR/IFF Secondary Surveillance Radar/Identification Friend or Foe SSRAM Synchronous Static Random Access Memory SSRC Single Sideband, Reduced Carrier SSSC Single Sideband, Suppressed Carrier SST (1)Supersonic Transport (aircraft) SST (2)Sea Surface Temperature SSTV Slow Scan Television SSW South-southwest SSYL Spanish language numbers transmission, female voice ST Send Timing (EIA-449) STA (1)Status (packet) STA (2)Special Temporary Authority (from FCC, to do something) STAJ Short Term Anti-Jam (makes gurgling noise on-air) STAMIS Standard Army Management Information System STANAG Standardization Agreement (NATO) [~] STANAG 4203 HF radio standards STANAG 4285 HF Single-tone modem, largely replaces RTTY STANAG 4415 Robust 75-baud single-tone modem STANAG 4529 Wideband single-tone modem STANAG 4538 Third-generation HF autolinking (3G ALE/ARCS) STANAG 4539 HF single-tone waveforms, also see MIL-STD-188-110 STANAG 5066 Profile for HF data communication STAR (1)SHARES Transportable Auxiliary Radio STAR (2)Standard Arrival STARC State Area Command (Army NG) STARS (1)Space-based Telemetry And Range Safety STARS (2)Secure Tactical Army Radio System STARS (3)Standard Terminal Automation Replacement System STARS-V Secure Tactical Army Radio System-VHF STAT Old CP/M status command, replaced in version 3.0 STCICS Strike Command Integrated Communications System (RAF) STD (1)Standard STD (2)Solar-Terrestrial Dispatch, Canadian auroral warning center STDMA Self-organizing Time Division Multiple Access STEM Science, Technology, Engineering, Mathematics (education) STG Satellite Tracking Group STK Strike Control sTLD Sponsored Top Level Domain (.aero, .coop, etc) Stn Station STP Shielded Twisted Pair (cable) STPD standard temperature, pressure, dry STRATCOM U.S. Strategic Command STS Space Transport System, the "Space Shuttle" STSA Standard Telemedicine System Architecture STT Shore Targeting Terminal STU Secure Telephone Unit STU-III Secure Telephone Unit, Third Generation STX Start Of Text (ASCII) SUA/ISE Special Use Airspace/Inflight Situational Enhancement SUB Substitute (ASCII) SUNA Sudan News Agency SUO Small Unit Operations SUP Sailors' Union of the Pacific SuperDARN Super Dual Auroral Radar Network suppl supplement SURFnet Dutch academic network SUV Sport-Utility Vehicle svcs services SV-CW-C Greek Telegraphy Club, aka GTC SVP (1)Single Line Variety Package (telco) SVP (2)Si Vous Plait ("If you please" in French) SVT (1)Sveriges Television (Swiss TV network) SVT (2)Secure Voice Terminal SW (1)Shortwave (high frequency - HF) SW (2)Southwest SWBC Short Wave Broadcasting SWED-ARQ Swedish ARQ teleprinter system, used by that country SWF Short Wave Fadeout (ionospheric disturbance) SWI Special World Interval, unscheduled radio astronomy observation period for solar event SWIM System Wide Information Management SWL Shortwave Listener SWR (1)Standing Wave Ratio SWR (2)Surface-Wave Radar SWS Standard Workstation (US Coast Guard) SX (1) Simplex SX (2) Old Hallicrafters prefix, usually meant radio had xtal filter SYMPA Systeme de Multi-Postage Automatique (French mailing list program) SYN Synchronous Idle SYNOP Synoptic weather reports (from surface observations) Sysop System Operator, the king on a BBS T (1)US Coast Guard C3 office, DC; aka G-T T (2)Boston transit system t Time (in seconds) T/R Transmit/Receive switching T1 Relatively high speed data connection over phone line T2FD Terminated, Tilted, Folded Dipole tac tactical TAC Tactical Air Command, now ACC TAC Technical Advisory Committee TACACS Terminal Access Controller Access Control System (Cisco) TACAMO Take Charge And Move Out (US Navy CP aircraft) TACAN Tactical Air Navigation TACC (1)Tanker/Airlift Command Center (US AMC) TACC (2)Tactical Aircraft Control Center (US) TACFIRE Tactical fire direction system TACS Terminal Access Conversion Service (UK) TACS Traffic Alert and Collision Avoidance System TACSAT Tactical satellite TACSATCOM tactical satellite communications TACT Tailored Annual Cutter Training (USCG) TACTS Tactical Aircrew Combat Training System TAD Temporary Additional Duty TADIL Tactical Digital Information Link (NATO) TAF Terminal Aerodrome Forecast, aviation weather TAFB Tropical Analysis and Forecast Branch (TPC) TAI International Atomic Time TAL Transoceanic Abort Landing (space shuttle) TALCE Tanker Air Lift Control Element TANJUG Old Yugoslav news agency TAO Tactical Action Officer TAOC Tactical Air Operations Center TAP Telocator Alphanumeric Protocol (paging) TAPR Tuscon (AR) Amateur Packet Radio, ham software source tar Tape Archive, Unix backup/archive program TARBS Television and Radio Broadcasting Services (Australia) TARPS Tactical Airborne Reconnaisance Pod System TARPS-DI TARPS Digital Imagery TAS True Air Speed TASCOMM Terrestrial Air-Sea Communications (UK) TASMA Two-meter Area Spectrum Management Assn. (Amateur) TAW Tactical airlift wing TAWC Tactical Air Warfare Center TBA To Be Announced TBD To Be Determined TC Telecommunications Specialist (old USCG grade, was RM) TCAS Traffic (Alert) & Collision Avoidance System TCC Telecommunications center TCF Tactical combat force TCH Threshold Crossing Height TCM Trellis Coded Modulation TCN Track Condition Notice (railroad) TCP Transmission Control Protocol TCP/IP Transmission Control Protocol/Internet Protocol TCPA Time to Closest Point of Approach TCPOD Tropical Cyclone Plan Of the Day TCS (1)Tactical Control System TCS (2)Tactical Camera System TCU Towering Cumulus TCWF Terminal Convective Weather Forecast TD (1)Transmitted Data, short for TXD TD (2)Transmitter/Distributor (old RTTY) TD (3)Tropical Depression TDA Table of distribution and allowances TDD Time Delay Distortion TDM Time-Division Multiplex TDMA Time Division Multiple Access TDOA Time Difference Of Arrival TDP Takeoff Decision Point TDU Threat Display Unit TDY Temporary duty ("to go TDY") TEC Total Electron Content (of ionospheric region) TECG Tactical Exercise Control Group TEI Text Encoding Initiative Telco Telephone Company ("The phone company") Telcom Telephone communication TELCOR Telecommunications Operating Requirements (USN) Telecom Telecommunication Teletext Short text messages, usually in TV blank interval TELINST Telecommunications Instructions Telnet Internet or dialup protocol for remote login TEMPEST Telecommunications Electronics Material Protected from Extraneous Spurious Transmissions (secure enclosure for computers, etc.; prevents eavesdropping) TEMPO Temporary weather change TERPES Technical Electronic Processing and Evaluation System TESTM Metar Test Message TEU Twenty-foot Equivalent Unit, container shipping TEXN Traffic Exchange Network (MARS) Tfc Traffic tfc Traffic TFE Tactical field exchange TFEO Tactical field exchange officer TFN Till Further Notice TFR Temporary Flight Restriction TFT (1)Thin Film Transistor TFT (2)Task Force Terminal TFW Tactical Fighter Wing THAAD Theater High Altitude Area Defense THD Total Harmonic Distortion (audio, in %) THFRS Transformation High-Frequency Radio System THREATCON Threat Condition (Alpha, Bravo...) TIA (1)Telecommunication Industry Association (UK) TIA (2)Thanks in advance TIA (3)The Internet Adaptor, old SLIP emulator from dialup shell TIBS (1)Tactical Information Broadcast System TIBS (2)Telephone Information Briefing Service TIDLS Tactical Information Data Link System TIFF Tagged Image File Format, versatile computer graphic standard TIGER Topologically Integrated Geographic Encoding and Referencing TIM Time Intermodulation distortion (audio) TIN Taxpayer Identification Number (same as SSN - FCC forms) TIP Threat Image Projection TIS (1)Traveler's Information Station TIS (2)Trusted Information System TIS (3)This Is (ALE) TIS (4)Traffic Information Services TIS-B Traffic Information Services-Broadcast TISCOM Telecom & Information Systems Command, VA (USCG) TKAP Transmitter Keep-Alive Program TKIP Temporal Key Integrity Protocol TLA Three-Letter Acronym (NASAspeak for NASAspeak) TLD Top Level Domain (.com, .org. .net, etc) TMA Terminal Area TMC (1)Technical Materiel Corporation, out of business TMC (2)TeleMonteCarlo, Monaco TMDE Test, measurement, and diagnostic equipment TMMMC Theater medical materiel management center tms Teams TN ("Tango November") Track number (ASW) TN3270 Telnet for IBM mainframes, emulates old 3270 terminal TNC (1)Terminal Node Controller (packet) TNC (2)Threaded Neill-Concelman (connector) TNC (3)Threaded Navy Connector (alternate) TOA Time Of Arrival TOC Tactical Operations Center TOD (1)time of day TOD (2)Tactical Ocean Data TOD (3)Target Offset Distance TOD (4)Takeoff Distance TODS TFR Operations Display System (see TFR) TOE (1)Table(s) of organization and equipment TOE (2)Theory of everything (physics) TOR Teleprinting (or Telex) over Radio TOW (1)Tube-launched Optically-tracked Wire-guided missile TOW (2)Terminal orderwire TOW (3)Time Of Week (see GPS) TOW (4)Takeoff Weight TPC Tropical Prediction Center, Miami, FL TPFDD Time-phased force and deployment data tpi Turns per inch T-Plex 8-frequency duplex ARQ teleprinter system TPM Technical Protection Measures TPO Transmitter power output TPR Third-Party Relay TPRAM Triple Port RAM TR Transmit-Receive TRACAB Terminal RAdar control in the tower CAB TRACE Transition Region And Coronal Explorer (NASA) TRACON Terminal Radar Approach Control TRADOC United States Army Training and Doctrine Command trans Transportation TRANSCOM Transportation Command TRC (1)Tactical Radio Communication TRC (2)Transmission Release Code TRI-TAC Joint Tactical Communications trmt Treatment TRSA Terminal Radar Service Area TRT Tropical RadioTelegraph, once owned by United Fruit Co TRUEX Training in Urban Environment Exercise (USMC) TS (1)thunderstorm TS (2)Tropical Storm TS (3)top secret TSA Transportation Security Administration TSB Technical Support Branch (TPC) TSC (1)Tactical Service Center (US Navy) TSC (2)TRICARE Service Center (US Navy medical) TSC (3)Terrorist Screening Center TSC (4)Technical Subcommittee (of IRAC) TSC (5)Training Systems Contract TSC (6)Training Support Center TSCC (1)Tactical Surveillance Control Center (US Navy) TSCC (2)Transportation Security Control Center (TSA) TSCC (3)Trauma Symptom Checklist for Children TSCC (4)Telemetry Standards Control Committee TSCC (5)Telemetering Standards Coordination Committee TSCC (6)Tracking Signal Corrections Counter TSCM Technical surveillance countermeasures (antibugging) TSGT Technical Sergeant TSNO thunderstorm information not available TSOP Thin Small Outline Package TSP (1)Telecommunications Support Plan (NCS) TSP (2)Telecommunications Service Priority (NCS) TSR Terminate and Stay Resident (IBM programming) TSSR Tropospheric Scatter (TROPO)-Satellite Support Radio TTL (1)Transistor-Transistor Logic TTL (2)Time To Live (of Internet packets or DNS records) TTL (3)Talk To ya Later TTL (4)Through The Lens TTP Trusted Third Party (for authentication of public keys) TTT CW prefix: Distress call follows TTWCS Tactical Tomahawk Weapon Control System TTY Teletype TTYL Talk (Type) To You Later (Internet) TU (1)CW brevity: Thank you TU (2)Terminal unit (old current-loop RTTY) TUBA TCP and UDP with Bigger Addresses (possible Internet extension) TUNES Spanish group callsign: Todos las Unidades y Establecimientos navales TV Television TVA Tennessee Valley Authority (big dam operator) TVC Televisió de Catalunya (Catelan TV, Barcelona) TVI Television interference TVNZ Television New Zealand TWA (1)Trailing-wire antenna (USN ELF/Tacamo) TWA (2)Tilt Whip Adaptor (US Army) TWA (3)Trans World Airways TWAIN (1)Toolkit Without An Important Name (Standard graphic scanner interface) TWAIN (2)Technology Without An Interesting Name TWAS This Was (ALE) TWEB Transcribed Weather Broadcast Twinplex Four-frequency duplex teleprinter system TWR (1)tower TWR (2)Trans World Radio TWT Traveling Wave Tube TWX Teletype Wide-area eXchange tx Transmitter, talk TXD Transmitted Data (Serial I/O modem line) txt (1)Extension: file is unformatted ASCII text (computers) txt (2)Text U CW brevity code: "You" U Up U/L (1) Uplink U/L (2) Upload UA (1)Packet control frame: Unnumbered Acknowledgement UA (2)User Agent (Internet) uA Microamp UART Universal Asynchronous Receiver/Transmitter (computer) UAT (1)Universal Access Transceiver UAT (2)Until Advised (by the) Tower U-ATA Ultra-AT Attachment UAV Unmanned Aerial Vehicle (USAF) UCVE Unconfined Vapor Cloud Explosion UDP User Datagram Protocol, (streaming) UDRE User Differential Range Error (GPS) UDT (1)Universal Dataflow and Telecommunications UDT (2)Underwater Demolition Team, crack USN WWII unit UEJ Unattended Expendable Jammer uf Microfarad UFN Until Further Notice UFO (1)Unidentified Flying Object UFO (2)UHF Follow On, new Navy COMSAT UGR Unitized group ration UHF Ultra High Frequency (300-3000 MHz) UI (1)User Interface UI (2)Packet designator: Unnumbered Information UI (3)User Initiated UICC Universal Integrated Circuit Card UID User Identification UIDL User Initiated Download UIN Universal Internet Number (ICQ) UK United Kingdom UKADGE UK Air Defense Ground Environment UKCC United Kingdom Control Center UKMACCS United Kingdom Maritime Coastal Communications System UKMET United Kingdom Office of Meteorology (also a model) UKNET UK network for UUCP UKSOF UK Satellite operations facility, part of NATO UL (1)Upload UL (2)Unauthorized launch UL (3)Underwriters' Laboratories ULS Universal Licensing System (FCC) UMT Unit ministry team UMTS Universal Mobile Telecommunications System UN United Nations UNB Universal Magnetic Balun uncl unclassified UNCLASS Message is not classified [~] UNCLOS United Nations Convention on the Law of the Sea UNF (1) UN Forces UNF (2) Unformatted UNHCR UN High Commission for Refugees UNI User Network Interface Unid Unidentified Uniden Unidentified UNIFIL UN Interim Forces, Lebanon U-NII Unlicensed National Information Infrastructure Univac Universal Automatic Computer, once IBM's main competition Unix Not an acronym; computer op-system derived from MULTICS [~] Unk Unknown UNO United Nations Organization UNPROFOR UN Provisional Forces UNSCOM UN Special Commission (Iraq inspectors) UP (1)CW prosign: "change to working frequency" UP (2)unknown precipitation UPnP Universal Plug and Play UPS (1)Uninterruptible Power Supply UPS (2)United Parcel Service UR CW brevity code: "Your" URE Unión de Radioaficionados Espańoles Ureq User request (computer return code) URL Universal Resource Locator (World Wide Web) URSI International Union of Radio Science URSIGRAM Coded solar-terrestrial report, originally from URSI US (1)United States US (2)Unit Separator (ASCII) USA (1)United States of America USA (2)US Army USA (3)Underground Service Alert ("dial before you dig") USA (4)Unit self-assessment USAAF United States Army Air Forces (WWII) USACE US Army Corps of Engineers USADA US Department of the Army USAF US Air Force USAFA US Air Force Academy USAFAWC US Air Force Air Warfare Center USAFE US Air Forces, Europe USAIS US Army Intelligence and Security Command, VA USAMMA US Army Medical Materiel Agency USANG (1)US Army National Guard USANG (2)US Air National Guard USAR (1)Urban Search & Rescue USAR (2)US Army Reserve USAREUR US Army, Europe USARSPACE US Army Space Command, part of USSPACECOM USART Universal Synchronous/Asynchronous Receiver/Transmitter USASC US Army Signal Command USASCH US Army Support Command Hawaii USASDC U.S. Army Strategic Defense Command, now USASSDC USASI US Army Space Institute USASSDC US Army Space and Strategic Defense Command, formerly USASDC USAV US Army Vessel USAWC US Army War College USB (1)Upper Sideband USB (2)Universal Serial Bus USC (1)United States Codes (Federal statute law) USC (2)Unified Space Command, now USSPACECOM USC (3)Up S[pit] Creek USCENTCOM US Central Command USCG US Coast Guard USCGA US Coast Guard Auxiliary USCGC US Coast Guard Cutter USCGR US Coast Guard Reserve USCS US Customs Service (now CBP and ICE) USCSIS United States Space Command Space Intelligence System USD US Dollars USDA US Department of Agriculture USELMNORAD US element, North American Aerospace Defense Command USENET "User Network," huge volunteer organization that propagates "News," not necessarily over Internet USEUCOM US European Command USFJ US Forces, Japan USFS US Forest Service USFWS US Fish and Wildlife Service USG (1)US Gallons (about 4 liters) USG (2)US Government USGS (1)US Coast & Geodetic Survey USGS (2)US Geological Survey USIA US Information Agency USKA Union Schweizerischer Kurzwellen-Amateure (Swiss ham assn) USLANTCOM US Atlantic Command USM US Marshal USMA US Military Academy USMC US Marine Corps USMCR US Marine Corps Reserve USMS US Marshals Service USMTF United States Message Text Format USN US Navy USNA US Naval Academy USNG US National Guard USNO US Naval Observatory USNR (1) US Naval Reserve USNR (2) US Navy, Retired USNS US Naval Ship USO United Service Organizations USOS Unshift On Space USP University of the South Pacific (Fiji, classes by radio) USPACOM United States Pacific Command USPHS United States Public Health Service USPS (1)United States Postal Service USPS (2)US Power Squadrons USR (1)User USR (2)US Robotics (old modem mfgr) USS United States Ship USSOCOM US Special Operations Command USSOUTHCOM U.S. Southern Command USSPACECOM U.S. Space Command USSS United States Secret Service USSTRATCOM U.S. Strategic Command USTA United States Total Army USTRANSCOM United States Transportation Command USVI US Virgin Islands UT (UT0 - UT3) Universal Time scales (corrected constantly) UTB Utility Boat UTC (1)Universal Time, Co-ordinated (corrected with leap sec.) UTC (2)Coordinated Universal Time uTLD Unsponsored Top Level Domain (.biz, etc) UTP Unshielded Twisted Pair (hardwired networks) UUCP Unix-to-Unix Copy Program (Unix file transfer s/w) Uudecode Unix program, converts uuencoded files back to binaries Uuencode Unix program, converts binary files to ASCII for transfer uuf Micro-microfarad, now pf (picofarad) uV Microvolt UV Ultraviolet uW Microwatt UWB Ultra Wideband UWC Universal Wireless Communications consortium UX User eXperience UXB Unexploded Bomb UXO Unexploded Ordnance V (1)Voltage (electromotive force) V (2)Variable V (3)Verification v Velocity VA (1) CW prosign: "End of transmission" VA (2) Volt-amps (as in a power supply) VA (3) Veteran's Administration VA volcanic ash VAAA Voice Activated Auto Attendant (telco) VAAT Voice Activated Audio Text (telco) VAB Vehicle Assembly Building (NASA) VABP Voice Activated Blue Pages (telco) VAC Volts Alternating Current VAD Voice-Activated Dialing (telco) VADM Vice-Admiral VAFB Vandenberg Air Force Base (CA) VAIVR Voice Activated Interactive Voice Response (telco) VAL Visiting Aircraft Line VANC Voice-Activated Network Control (telco) VAPD Voice Activated Premier Dialing (telco) VAS VOLMET Automation System VASI Visual Approach Slope Indicator VAX (1)Variable Address Extension (old DEC Computer) VAX (2)English vacuum cleaner brand : ) VAX/VMS VAX Virtual Memory System, op-system for above VBI Vertical Blanking Interval (TV) vBNS Very high speed Backbone service (US) VBR Variable Bit Rate VBS Visual Basic Scripting (Microsoft security nightmare) VC (1)in the vicinity VC (2)Viet Cong, obsolete VC01 Voice Chip #1, robotic Chinese numbers station Vcc Collector voltage VCO Voltage-Controlled Oscillator VDC Volts Direct Current VDE Video Display Editor, at one time standard freeware CP/M & PC text editor VDL VHF Data Link (ARINC) VDL2 VHF Data Link 2 VDLC Virtual Data Link Capability VDLM2 VDL, Mode 2 VDSL Very high-data-rate Digital Subscriber Line VDSL Very-high-bit-rate Digital Subscriber Line VDT Video Display Terminal VDU Video Display Unit VE Volunteer Examiner (Amateur) VEC Volunteer Examiner Coordinator (Amateur) VENONA Old US codeword for its USSR decryption program 1943-1980 [~] VESA Video Equipment Standards Association, computer displays VESREP Standard report from commercial fishing vessel VEUR European Volmet VF (1)Voice frequency VF (2)Velocity Factor VF (3)Fighter squadron (USN) VFAT Virtual File Allocation Table (MS-Windows) VFO Variable Frequency Oscillator VFR Visual Flight Rules VFT Voice Frequency Telegraphy (multiplex RTTY) VFCT Voice Frequency Carrier Telegraphy VHF Very High Frequency (30-300 MHz) vi Visual Editor, full-screen text editor for Unix VICS Vehicle Information Communication System VIN Vehicle Identification Number VIP Very Important Person VIS visibility VISNO visibility at secondary location not available VLB VESA Local Bus; PC display bus, now usually done by the PCI VLF Very Low Frequency (3-30 kHz) VLM Virtual Loadable Module (Novell) VM (1)Voice mirror VM (2)Virtual memory VMC Visual Meteorological Conditions VMS Virtual Memory System, good but obsolete DEC OS VNA Viet Nam News Agency VNAV Vertical Navigation Vne Absolute top speed of an aircraft; "never exceed" VOA Voice Of America Vocoder Voice coder VOH Voice Of Hope (KVOH, religious broadcaster) VoIP Voice Over Internet Protocol VOLMET Flight weather transmission, for planes in route Volt Unit of electrical potential, named for Alessandro Volta VOM Volt-Ohm Meter VOMUX Voice Multiplexer VOR (1)VHF Omnidirectional Ranging (Aircraft NAVAID) VOR (2)Voice Of Russia VORTAC Ground station combining VOR and TACAN VOX Voice operated switching VPF Vertical Processing Facility (NASA) VPN Virtual Private Network VR (1)Voltage regulator VR (2)Visual Route (air training route) VRAM Video RAM VRB Variable wind VRC (1)Vehicular Radio Communications (AN/VRC-xxx) VRC (2)Vehicular radio configuration (Army) VRC (3)Vertical Redundancy Check, fancy name for parity (computers) VRML Virtual Reality Modeling Language VROC Vertical rate of climb VRT Vlaamse Radio- en Televiseomroep (Belgian) VSAT Very Small Aperture (Antenna) Terminal VSC Vertical Service Code (telco features - start with *) VSFC Virginia Space Flight Center, Wallops Island vsh Visual Shell, clunky full-screen command interpreter for Unix VSWR Voltage standing wave ratio VT (1)Vertical Tab (ASCII) VT (2)Valid Time (wx forecasts) VTnnn Series of old DEC terminals, still a popular emulation code VTP Virtual Terminal Protocol VTS Vessel Traffic Services VTVM Vacuum-tube voltmeter VU Volume Units VUFER VHF/UHF Frequency Experimental Radio VV Vertical Visibility (of obscured sky) VVV CW test group VWS Virtual Warning System VxD Virtual Device Driver (MS-Windows) VXO Variable Crystal Oscillator VY CW brevity code: "Very" W Power, in watts W west W Whisky ("Benchmark Whisky" is USN offset) W3C World Wide Web Consortium WA (1)CW prosign: word after WA (2)Work Authority (railroad orders) WABNRES Worldwide Airborne Resources (command a/c) WAC (1)Worked All Continents (amateur award) WAC (2)Women's Army Corps, obsolete WAC (3)World Aeronautical Chart WACN Wide Area Communications Network WAD Wide-Area Domain (computer games) WAFS World Area Forecast System, satellite delivered air wx WAGB USCG designation for icebreaker WAIS Wide-Area Information Server WAM Wide Area Multilateration WAMS Wide Area Master Station WAN (1)Wide-Area Network WAN (2)Wide-Area Network Station WAP (1)Wireless Application Protocol WAP (2)Wireless Access Point WARC World Administrative Radio Conference WARN Weather Amateur Radio Network, see SKYWARN WARP Weather and Radar Processor WAS (1)Wide-Area Surveillance WAS (2)Worked All States (US amateur award) WAS/MTI Wide Area Surveillance/Moving Target Identification WATS Wide Area Telephone Service WAZ Worked All Zones (amateur award) WB (1)Wideband WB (2)CW prosign: word before WB (3)Welcome Back (Internet) WB (4)Warner Bros (Good movie studio, lousy TV network) WBFM Wideband frequency modulation WBU World Broadcasting Unions WBU-ISOG WBU Inter-Union Satellite Operations Group WBU-TC World Broadcasting Unions Training Centers WCDMA Wideband Code Division Multiple Access WCRP World Climate Research Program WCS (1)Wireless Communications Service WCS (2)Waste Collection System (Space shuttle potty) WDC World Data Center, any of several for solar-terrestrial obs WE Western Electric WEFAX Weather Facsimile WEMA Work Equipment Movement Authority (railroad orders) WEMF World Electronic Media Forum WEP Wired Equivalent Privacy (wireless LANs; insecure) WFAS Wildland Fire Assessment System (USFS) WFM Wideband FM WFN War Fighter Net WFO Weather Forecast Office WG Working Group (ITU) WG/SO Working Group for Surface Observations WGI World Geophysical Interval (research observation period) WGS-84 World Geodetic System, 1984 WHCA White House Communications Agency WHEC High-Endurance Cutter (USCG) WHISC Western Hemisphere Institute for Security Cooperation (see SOA) whoami Returns name you are logged in under (Unix) [~] whois Internet lookup program for finding people by querying servers [~] WIE With Immediate Effect WIFCOM Wirefree communications (US Navy) Wi-Fi Wireless Fidelity, 802.11 standard interface; originally 802.11b Wilco Voice prosign: Will comply WIMAX Worldwide Interoperability for Microwave Access WIMP (1) Window, Icon, Mouse, Pointer (graphical interface) WIMP (2) Weakly Interacting Massive Particle WINS Windows Internet Naming Service WINSOCK Windows Sockets API, used for networking from Microsoft s/w WISE Web-Integrated Software metrics Environment WIU Wayside Interface Unit (railroad) WIX USCG designation for training barque Eagle Wkg Working WL Wordlength, size of basic data group (computing) WLAN Wireless Local Area Network (computing) WLB Seagoing Buoy Tender (USCG) WLI Inland Buoy Tender (USCG) WLIC Inland Construction Tender (USCG) WLIS We Love Interval Signals (Pirate) WLL wireless local loop WLM Coastal Buoy Tender (Medium Endurance USCG vessel) WLR River Buoy Tender (USCG) WMD (1)Weapons of Mass Destruction WMD (2)Weapons of Mass Distraction (psyops tongue-in-cheek) WMD-CST Weapons of Mass Destruction Civil Support Team WMEC Medium-Endurance Cutter (USCG) WMM (1)Wi-Fi Multimedia WMM (2)World Magnetic Model WMO World Meteorological Organization WMR World Music Radio WMSCR Weather Message Switching Center Replacement WMTS Wireless Medical Telemetry Service WMV Windows Media Video WND wind WNW West-northwest WO Work order WORM Write-Once Read-Many (CD-R, allows making own CD-ROMs) Wouff Hong Scary wooden device supposedly used on posteriors of hams causing QRM (ARRL lore) [~] WPA Wi-Fi Protected Access (Also WPA2) WPB Patrol Boat (USCG) WPC Weather Prediction Center (US) WPM Words per minute WPS Wi-Fi Protected Setup WRAPA Work Restricted Authority/Protect Against (railroad orders) WRC World Radio (Communications) Conference WRCC Western Regional Climate Center (NOAA) WRF Weather Research and Forecasting (model) WRTH World Radio TV Handbook WRU Who Are You? (RTTY) WSHFT wind shift WSL Weapons Survivability Lab WSM Weapon system manager WSMR White Sands Missile Range (NM) WSO Weapon Systems Officer ("Whizzo") WSQ Weak Signal QSO (Amateur MFSK mode; usually WSQ2) WSRO Weapon system replacement operations WST Weather Station WSTF White Sands Test Facility (NM) WSW West-southwest WT (1)Walkie-talkie WT (2)Wireless Telegraph (Morse or RTTY) WTB (1)Wireless Telecommunications Bureau (FCC) WTB (2)Want To Buy (radio swap ads) WTDD Wayside Train Defect Detector (hotbox/dragger detector) WTGB 140' Icebreaking Tug (USCG) WTLD Wayside Train Length Detector WTMD Walk-Through Metal Detector WU Western Union WUAN Wireless Universe Area Network WUN World Utility News, Internet group, maintains large e-mail list, rhymes with "one" WVDC Working Voltage, DC (capacitors) WW Weather Warning WWABNCPP Worldwide Airborne National Command Post Program WWCR (1)World Wide Christian Radio (callsign) WWCR (2)World Wide Conspiracy Radio (facetious) WWMCCS Worldwide Military Command and Control System, obsolescent WWNWS World Wide Navigational Warning Service WWRB World Wide Religious Broadcasters (callsign) WWV NIST standard frequency & time station, Boulder, CO WWVB NIST Boulder, CO, low frequency standard broadcast WWVH NIST standard frequency & time station, Kekaha, HI WWVL Old NBS low-frequency time stn, no longer on air WWW World Wide Web, aka W3, www, Web, World Wide Wait Wx Weather WXP Weather Processor (Computer program) WYFR We're Your Family Radio (Callsign) WYSIWYG What You See Is What You Get (computers) X (1) Reactance, in ohms X (2)(Also "Xray") prosign for end of sentence XAML eXtensible Application Markup Language (mickeysoft) X-band (1)8-12 GHz microwave band X-band (2)Expanded AM band, 1610-1720 kHz XCHS Extended Cylinder, Head, Sector (addressing) xcvr Transceiver xfmr Transformer XINU XINU Is Not UNIX (recursive and retrograde) xistor Transistor xmit Transmit mode XML eXtensible Markup Language xmlns XML namespace XMODEM Async file transfer protocol, uses 128-byte or 1K packets, over direct links, not Internet XMPP Extensible Messaging and Presence Protocol XMS Expanded Memory System (IBM PC, different spec from EMS) xmsn Transmission xmt Transmit mode xmtr Transmitter XO Executive officer Xon/Xoff Computer serial flow control, usually using DC3/DC1 (^S/^Q) XPND Expand xponder Transponder XSD XML Schema Definitions (see XML) XSL eXtensible Style Language XSS (1)Cross Site Scripting (Computer security) XSS (2)eXperimental Satellite System (USAF) XSS (3)eXtremely Simple Syndication (news feed) XSS (4)Callsign for new UK/NATO ALE system [~] XT eXtra Value (PC-XT was first IBM PC with a hard disk; obsolete) XTACACS Extended Terminal Access Controller Access Control System (Cisco) xtal Crystal XTP eXpress Transfer Protocol (computers) XUL (1)XML User-interface Language XUL (2)eXtensible User-interface Language X-windows Standard windowing system for networks (usually Unix) [~] XXX (1)CW prefix: traffic is urgent (same as SECURITE) [~] XXX (2)Set of standards for X.25 PAD packet networking XYL Wife ("ex-young lady") Y2K Year 2000, or resulting computer bugs (geekspeak) YAHOO Yet Another Heirarchical Officious Oracle; may be a back-formation, as guys who started Yahoo! styled themselves as just yahoos YB Yacht Boy (Grundig radio line) YF CW brevity code: "Wife," more typically "XYL" (eX-Young Lady) YL Female voice ("Young Lady") YLE Yleisradio (Finland, not an acronym) YMMV Your Mileage May Vary (cardinal rule of HF) YMODEM Along with YMODEM-G, improved async file transfer protocol [~] Z (1)Zulu time, standard time on 0 meridian, like UT Z (2)Impedance (in ohms) Z (3)This message has FLASH precedence Z-80 Early 8-bit processor chip, used by CP/M, still made ZAA Z-code: You have improper circuit discipline ZAE Z-code: I am unable to receive you ZAN Z-code: We have absolutely negative copy ZBI UK Military Z-code: Switch to voice mode ZBO Z-code: (INT ZBO Do you have traffic (of precedence...) for me?) I have traffic (of precedence...) for you ZBR Z-code: Break for retuning ZBZ Z-code: (INT ZBZ: What is my signal's printing acceptability? (1-5) ) Your signal's printing acceptability is (1-5) Z-Count 29-bit binary GPS time stamp (17 LSBs are broadcast) ZCP Z-code: I have poor conditions; please use full power ZCPR3 Small Z-80 operating system, improved on CP/M, obsolete ZDE Z-code: Message undelivered ZDF Z-code: Message delivered ZEN Military Z-code: Message has been copied to... ZFD Military Z-code: Message may be a duplicate ZFG Military Z-code: Message is a duplicate and is to be forwarded ZKI Z-code: Listen [on _ kHz] ZKR Z-code: I have a radio watch on _ kHz ZNC Z-code: I have no communication with _ ZNG Z-code: Band conditions no good for copy ZNI Z-code: No station ID heard ZNJ Military Z-code: Message has been sent to... ZNK Military Z-code: Addressees who do not hold cryptographic facilities are exempted ZNR Military Z-code: Msg may be forwarded without change by radio or non-approved circuit ZNR UUUUU Security Warning Signal: Message is Unclassified or offline encrypted - OK to forward unchanged on any circuit ZNX You have disclosed an EEFI (1-10; see EEFI) ZNY Military Z-code: Do not forward this message unencrypted by radio or non-approved circuit. ZNY CCCCC Security Warning Signal: Message is CONFIDENTIAL ZNY RRRRR Security Warning Signal: Message is RESTRICTED ZNY SSSSS Security Warning Signal: Message is SECRET ZNY TTTTT Security Warning Signal: Message is TOP SECRET ZRF Zero Retention Force ZRO Z-code: How copy? ZSR Z-code: You are strong-readable ZUC Z-code: Unable to comply until ---- ZUH Z-code: Unable to comply ZUT (1)Unofficial Z-code: "CW Forever!" (see CW) ZUT (2)Zeta Upsilon Tau, 60s US Coast Guard radio op society ZWEI ZWEI Was EINE Initially (recursive acronym; see EINE) ZWR Z-code: You are weak-readable ° degrees µ micro µµF micro-microfarad, now pF µH microhenry µV microvolt Police/CB 10-codes: 10-1 Your signals are being received poorly 10-2 Your signals are loud & clear 10-3 Stop transmitting 10-4 Your message is received ("Roger;" saying both is redundant) 10-5 Please relay 10-6 Station is busy 10-7 Out of service, radio off 10-8 In service, available 10-9 Please repeat message 10-10 Out of service, radio on 10-19 Go back to station/HQ 10-20 Location ("What's your 20?") 10-21 Use landline/phone 10-22 Cancel message 10-23 Stand by 10-27 Driver's license ID check 10-28 Vehicle registration check ("Rolling 28" -CHP) 10-33 All units stand by, frequency is on emergency status 10-97 I am arriving at assignment/ on scene ("I'm 97") 10-98 Assignment completed/ leaving scene 10-99 Emergency; equivalent to SOS and MAYDAY Other police codes: Code 1 Come in on the radio Code 2 Respond quickly, without lights/siren ("hurry") Code 2A Hurry faster - call is priority Code 3 Respond with lights/siren Code 4 No more help needed, situation stable Code 4A No more help needed, suspect still not in custody Code 5 Stakeout at (--), uniformed patrol stay away Code 6 Out of vehicle, on investigation Code 7 Out to lunch Code 10 Request clear frequency Code 20 Notify news media Code 30 Alarm Code 30A Alarm with audible suspects inside Code 33 Emergency, all units stand by Code 37 Vehicle is stolen (LAPD) Code Alpha Assemble at prearranged staging point (LAPD) Code Blue (1)Notify police Code Blue (2)Respiratory emergency (medical) Code Red (1)Notify fire department Code Red (2)Frequency is restricted (LAPD Metro) (your cops might be a bit different) Computer networking standards: IEEE 1394 "Firewire" high speed data transfer 56Kflex Telephone modem 56K, falling back in 2K increments from there. 802 Family of IEEE recommendations for computer networks 802.3 Ethernet, fast packet transfers, resembles wired radio 802.3ab Hot-rod Ethernet, one billion bits/sec over long copper 802.3u Provides auto-speed, autoselection of duplex 802.3z Hot-rod Ethernet, one billion bits/sec over fiber or twinax 802.11 Draft standard for wireless Ethernet 802.11 Original system; 1-2 Mbps using spread spectrum 2.4 GHz 802.11a 54 Mbps via 5-GHz orthogonal FDM 802.11b 11 Mbps in 2.4 GHz spread spectrum (Wi-Fi) 802.11g 20+ Mbps in 2.4 GHz SS 802.11n Multi-channel on both bands 802.12 Recommendation for 100BaseVG/ 100VG/ AnyLAN 10Base-2 IEEE 802.3 thin ethernet (high-speed computer networking) 10Base-5 IEEE 802.3 thick ethernet 10Base-F IEEE 802.3 ethernet over fibre-optic cable 10Base-T IEEE 802.3 ethernet over twisted pair cabling 1000Base Gigabit ethernet standards 1000Base-CX Short-haul over copper 1000Base-LX 1300nm multimode and single-mode fiber according to 802.3z 1000Base-SX 850nm multimode fiber according to 802.3z 1000Base-T Long-haul over copper according to 802.3ab 100Base-T IEEE 802.3 fast ethernet at 100Mbit/s 100Base-T4 Encoded 100Mbit/s over 4 pairs, obsolescent 100Base-TX encoded 100Mbit/s over 2 pairs 100Base-VG see 100VG-AnyLAN 100Base-X Encoded 100Mbit/s 100VG-AnyLAN 100Mb/s LAN carrying Ethernet or Token-Ring, obsolescent ATM Asynchronous Transfer Mode AAL ATM Adaptation Layer AAL-1 Synchronous adaptation layer designed for carrying voice trunk lines AAL-2 Adaptation layer intended for variable bit rate video, but never really got off the ground and is not offered by vendors AAL-3/4 Adaptation layer intended to be used by Frame Relay and SMDS and other delay-insensitive variable rate or bursty data traffic, but mostly now passed over in favour of AAL-5 AAL-5 'Simple and efficient adaptation layer' for computer networking Bell 103 300 bps FSK (US modem tones, see V.21) Bell 212A 1200 bps (US modem tones, see V.22) T1 Relatively high speed data connection over phone line V.nn Prefix for CCITT specs - these are for phone modems V.17 Fax modem spec, to 14400 bps V.21 aka "Bell 103," the old 300 bps modem spec, makes sound like RTTY V.22 aka "Bell 212A," 1200 bps modem spec, slight differences V.22bis Above spec extended to 2400 bps V.23 1200/75 bps modem spec V.24 data link spec - equiv RS232 V.25bis modem control sequence for international calls, lost out to Hayes V.26bis 2400bps half duplex synchronous, used for fax V.27ter 4800bps half duplex synchronous, used for fax V.28 Data link spec V.32 9600/4800bps V.32bis 14.4K/12K/9600/7200/4800bps V.32 terbo (V.32 bis ter) proprietary modem spec for 19,200 V.34 33.6K/31.2K/28.8K/26.4K/24K/19.2K/16.8K/14.4Kbps, then like V.32 V.42 LAPM error control, 1200bps and above V.42bis Data compression, 1200bps and above V.90 56Kb, falls back like 56Kflex V.FC V.Fast Class: unofficial, 19.2Kbps X.nn ITU-T (formerly CCITT) recommendations: X.PC Async version of X.25 for small computers X.10 Proprietary device control by signalling over AC lines X.21 balanced data signalling standard, 15 wires X.21bis Above, for 25 wires, unbalanced X.25 Packet communication protocols (AX.25 is amateur radio) X.27 37-pin data interface, adding handshake and flow control X.28 Standard interface, terminal to PAD X.29 Control packet standard for PAD and remote host, using X.25 X.3 PAD standard X.31 Network security protocol X.400 E-mail protocol X.413 Definition of message storage and forwarding X.419 Defines P3 and P7 protocols X.420 Defines interpersonal e-mail X.435 Defines control messages X.441 Defines voice messages X.500 Directory standard X.509 Digital security and identification # # #