Satellite Technology Glossary

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There are currently 2730 names in this directory
2P-PAP(Two)
Pulse Amplitude and Phase Modulation Modem
3DTV
3DTVThree Dimensional Television
4PDT
Four-Pole Double-Throw
4PST
Four-Pole Single-Throw
A
Ampere or Microampere
A-h
Amp-House or Ampere Hour
a.c. OR AC
Acquisition Cycle or Address Complete or Alternating Current or Assignment Channel
a.u.
Astronomical Unit
A/D
Analog to Digital Conversion or Analog to Digital Converter or Analogue to Digital
AAC
Automatic Amplitude Control or Autonomous Attitude Control
ABC
Automated Brightness Control
ABM
Apogee Booster Motor or Apogee Boost Maneuvers
ABS
Absent
ABU
Asia-Pacific Broadcasting Union
AC/DC
Alternating Current or Direct Current
ACAST
Advisory Committee on the Application of Science and Technology to Development (UN)
ACC
Administrative Committee on Coordination or Alarm and Control Consolidation or Alarm and Control Coordination or Alarm Consolidation Console or Alarms Control & Consolidation or Antenna Control Console or Automatic Chroma Control
ACCEL OR ACEL
Accelerometer
ACD
Automatic Call Distribution
ACDE
Attitude Control and Determination Electronics
ACDS
Attitude Control and Determination Subsystem
ACE
Attitude Control Electronics or Automatic Calling Equipment
ACI
Acknowledgment Signal Unit or Acquisition Cycle Interval or Adjacent Channel Interference
ACM
Acceptance Testing & Configuration Management
ACME
Analog Circuit Multiplication Equipment
ACP
Acquisition and Synchronization Processor or Attitude Control Processor or Automated Command Procedure
ACS
Attitude Control Subsystem
ACSSB
Amplitude Companded Single Sideband
ACTP
Abridged Condensed Time Plan
ACTS
Advanced Communication Technology Satellite (USA)
ACU
Acquisition Control Unit or Acquisition/Antenna/Attitude Control Unit or Adaptive Delta Modulation or Antenna Control Unit or Automatic Calling Unit
ADC
Analog to Digital Converter or Automatic Deviation Control
ADCE
Attitude Determination and Control Equipment or Attitude Determination and Control Electronics
ADCS
Analog Despin Control System or Attitude Determination and Control (Sub) System or Attitude Determination and Control Support
ADDER
Automatic Digital Data Error Recorder
ADDR
Address Complete
ADE
Automatic Design Engineering or Automatic Doppler Enhancer
ADF
Automatic Direction Finder
ADI
Alternate Digital Conversion
ADM
Adaptive Delta Modulation or Administrative Procedures Manual
ADMA
Administrative Committee on Coordination or Amplitude Domain/Division Multiple Access
ADP
Acquisition Phase UW Detection or Attitude Data Processor or Automatic Data Processing
ADPCM
Adaptive Differential Pulse Code Modulation
AEN
Equivalent Articulation Loss (USA)
AEROSAT
Aeronautical Satellite System
AF
Audio Frequency
AFC
Automatic Frequency Control
AFCAC
African Civil Aviation Commission or African Development Bank
AFSATCOM
Air Force Satellite Communications System (USA)
AFSK
Amplitude and Frequency-Shift Keying
AFT
Automatic Fine Tuning or Back; rear (after)
AGC
Automatic Gain Control
AGRIS
Agricultural Research Information Service (FAO - USA)
Ah
Ampere-Hour
AI
Articulation Index (of a speech circuit) or Artificial Intelligence
AIAA
American Institute of Aeronautics and Astronautics (USA)
AIBD
Asia-Pacific Institute for Broadcasting Development
AIRE
Alarm Indication to Remote End
AIS
Alarm Indication Signal or Alarm Inhibit System
AKM
Apogee Kick Motor
ALC
Automatic Light/Level Control
ALF
Absorption Limiting Frequency
ALGOL
Algorithmic Language
ALM
Apogee Lowering Maneuver
ALOHA
System developed by University of Hawaii to use RMA for Pacific island communications
ALT
Alternate or Altitude
ALU
Arithmetic Logic Unit
AM
Air Mass or Amplitude Modulation or Apogee Motor
AMA
Automatic Message Accounting
AMC
Assistant Maneuver Coordinator
AMDS
Automated Earth Station Monitor & Diagnostics System or Automated Monitor and Diagnostic System
AMF
Apogee Motor Fire/Firing
AMI
Alternate Mark Inversion (signal); (bipolar signal) or Amplitude Probability Distribution
AMS
Attitude Measurement Sensor
AMSAT
Radio Amateur Satellite Corporation (USA)
AMSL
Above Mean Sea Level
AMSS
Automatic Message Switching System
AMVFT
Amplitude-Modulated Voice Frequency Telegraphy or Analog to Digital Converter
ANC
Active/Automatic Nutation Control or Automatic Nutation Control
ANCS
Active Nutation Control(ler) System
AND
Type of logic circuit
ANDS
Active Nutation Damping System
ANG
Angle
ANI
Automatic Number Identification
ANIK
Domestic satellite network (owned by Telesat - Canada)
ANL
Automatic Noise Limiter
ANOD
Anode
ANS
Astronomical Netherlands Satellite (Netherlands/USA)
ANSI
American National Standards Institute (USA)
ANT
Antenna
ANTEL
Administraci n Nacional de Telecomunicaciones (El Salvador)
ANTELCO
Administraci n Nacional de Telecomunicaciones (Paraguay)
AOCS
Attitude and Orbit Control Subsystem
AOR
Atlantic Ocean Region
AOS
Acquisition of Signal
AP
Access Point
APC
Automatic Phase Control or Autonomous Payload Controler
APCS
Autonomous Payload Control System
APD
Acquisition Phase Unique Word Detection or Avalanche Photodiode Detector or Amplitude Probability Distribution
APE
Antenna Positioning Electronics
API
Application Program Interface
APK
Amplitude-Phase Keying
APKS
Amplitude-Phase-Keyed System
APL
Average Picture Level
APM
Antenna Positioning Mechanism or Apogee Boost Maneuvers or Apogee Motor or Combined Amplitude and Phase Modulation
APR
Asia Pacific Region
APS
Antennal Position Data Select Switch
APT
Asian Pacific Telecommunity or Automatic Picture Transmission
APTU
African Postal and Telecommunications Union
ARA
Angular Rate Assembly
ARABSAT
Arab Satellite Communication Organization
ARAEN
Reference system for the determination of the articulation reference equivalents
ARC
Atlantic Resotration Committee
ARE
Automatic Reconfiguration Electronics
ARENTO
Telecommunications organization (Arab Republic of Egypt)
ARIANE
Commercial European launch vehicle
ARIANESPACE
European Organization which operates ARIANE launch vehicle systems
ARIEL
Ionospheric satellite (UK)
ARM
Armed
ARP
Apparent Radiated Power
ARPA
Advanced Research Projects Agency (USA)
ARQ
Automatic Repeat Request
ARRL
American Radio Relay League (USA)
ART
Additional Reference Carrier Transmission
ARTI
Arab Regional Telecommunications Institute or Articulation Index or Articulation Reference Equivalent (UK)
AS
Articulation Score
ASA
American Standards Association
ASB
Anti-sideband
ASBU
Arab States Broadcasting Union
ASC
American Satellite Company (USA) or American Security Carrier or Automatic Selectivity Control
ASCII
American National Standard Code for Information Interchange
ASE
Airborne Support Equipment or Auxiliary State Estimator
ASEAN
Association of South East Asian Nations
ASETA
Asociacion de Empresas Estataless de Tellecomunicacion del Acuerdo Subregional Andino (Association of State-owned Telecommunications of Subregional Andean Agreement)
ASI
Asynchronous Serial Interface
ASIASAT
Asian satellite system supported by UK
ASK
Amplitude Shift Keying
ASL
Above Sea Level
ASP
Acquisition and Synchronization Processor or Aspect or Attitude System Processor
ASR
Automatic Send and Receive
ASSR
Acquisition and Steady State Reception
AST
American Society for Testing Materials
ASTRA
Application of Space Techniques Relating to Aviation or Satellite network (Luxembourg)
ASU
Acknowledgment Signal Unit or Acquisition and Synchronization Unit
ASWA
Adjustable Solar Wing Actuator
AT
Acceptance Test or Acquiring Terminal
AT&T
American Telephone and Telegraph Company (USA)
ATA
Aeronautical Telecommunications Agency (USA)
ATAA
Air Transport Association of America (USA)
ATB
All Trunks Busy
ATDA
Augmented Target Docking Adapter
ATECO
Automatic Telegram Transmission with Computers
Atlas/Centaur
Launcher (General Dynamics - USA)
ATM
Asynchronous Transfer Mode
ATME
Automatic Telegram Transmission with Computers or Automatic Transmission Measuring Equipment
ATMS
Automatic Transmission Measuring System
ATN OR ATTN
Attenuation or Attenuator
ATP
Abbreviated Test Plan
ATR
Answering Time Recorder
ATS
Advanced Technology Satellite
ATU
Arab Telecommunication Union
AURA
Astronomy research satellite (France)
AUTO
Automatic
AUTOMOON
Automatic Moon Correction
AUTON
Autonomous commanding
AUTOON
Automatic Ace Turn On
AUX EST
Auxiliary Estimator for Earth Chord
AVC
Automatic Volume Control
AVD
Alternate Voice/Data
AVRG
Average
AX
Axial
AYAME
Experimental Telecommunication Satellite (Japan)
AZ OR Az
Azimuth
B
Baud/bits per second or Bit or Magnetic Field Strength
B-ISDN
Broadband ISDN
B-MAC
Multiplexed Analog Component (TV, type B format)
B/W
Bothway
BA
Burst Acquired
BAI
Baikonur Launch Complex (Russian Federation)
BAPTA
Bearing and Power Transfer Assembly
BAPTA OR BPTA
Bearing & Power Transfer Assembly
BATELCO
The Bahamas Telecommunication Corporation (Bahamas)
BATT
Battery
BB
BaseBand
BBC
British Broadcasting Corporation (UK)
BBD
Broadband Transmission
BBTM
Beam-to-Beam Traffic Matrix
BBU
BaseBand Unit
BC
Broadcasting
BCD
Binary Coded Decimal
BCH
Bose-Chaudhuri Hocquenghem (FEC block codes)
BCM
Binary Coded Matrix/Block Coded Modulation
BCN
Beacon
BCRU
Battery Charging and Reconditioning Unit
BCS
Block Control Signal
BCTE
Bus Command & Telemetry Electronics
BCU
Batch Control Utility
BCW
Burst Code Words or Burst Control Signal
BDC
Battery Discharge Controler
BDE
Baseband Distribution Equipment
BDF
Baseband Distribution Frame
BDT
Bureau of Telecommunication Development (ITU)
BDU
Baseband Distribution Unit
BE
Beacon Explorer (NASA Satellite - USA)
BEEFS
Bit Error Ratio/Error Free Seconds
BEF
Band Elimination Filter
BEP
Bit Error Probability
BER
Bit Error Ratio
BERCONT
Bit Error Ratio Continuous
BEZEQ
The Israel Telecommunication Corp., Ltd.
BF
Branching Filter
BFDI
Bit-Frame Synchronizer Interface
BFN
Beam Forming Network
BFO
Beat Frequency Oscillator
BFS
Bit Frame Synchronizer
BFSI
Bit Frame Synchronizer Interface
BFSK
Binary Frequency Shift Keying
BH
Brinell Hardness
BHASKARA
Satellite for earth observation (India)
BHC
Busy Hour Call
BHL
Busy Hour Load
BIAS
Correction
BIE
Bearer Interface Equipment
BIH
Bureau International de l'Heure (International Time Bureau)
BINR
Basic Intrinsic Noise Ratio
BIP
Bit Interleaved Parity
BIPM
Bureau International des Poids et Mesures (International Bureau of Weights and Measures)
BIQUAD
Biquadratic Filter
Bit
A binary digit, Smallest possible unit of digital transmission or Rate Speed of digital transmission, measured in bits per second, or multiples (kilobits, megabits per second)
BITE
Built-In Test Equipment
BIU
Bus Interface Unit
BJT
Bipolar Junction Transitor
BLD
Binary Load Dump
BLK
Block
BM
Burst Monitor
BMLA
Burst Mode Microwave Link Analyzer
BMS
Baseband Matrix Switch
BMU
Battery Monitor Unit
BNA
Burst Not Acquired
BNQ
Burst Not Qualified
BNS
Back-up North-South Stationkeeping
BO
Backoff
BOD
Beneficial Occupancy Date
BOL
Beginning of Life
BP
Bandpass or Burst Processor
BPF
Bandpass Filter
BPI
Bits Per Inch
BPL
Bandpass Limiter
bps OR BPS OR bit/s
Bits Per Second
BPSK
Bi-Phase Shift Keyed
BPSK, (2-PSK)
Binary phase-shift keying
BQ
Burst Qualified
BRL
Balance Return Loss
BRS
B-Mode Receiving Station or Block Received Signal
BRT
Beacon Receive Terminal
BS
Backspace or Broadcasting Satellite System (Japan)
BSE
Broadcast Satellite, Experimental (Japan)
BSG
British Standard Gauge
BSI
British Standards Institute (UK)
BSM
Baseband Switch Matrix or Bypass Switch Matrix
BSP
British Standard Pipe (Thread)
BSS
B-Mode Sending Station or Broadcasting Satellite Service or Broadcasting Satellite System (Japan)
BST
Block the Spade Terminal Command
BSU
Baseband Switching Unit
BSWG
British Standard Wire Gauge
BSXF
Burst Synch Failure
BT
Bandwidth Time product
BTA
Burst Timing Acquired
BTE
Bench Test Equipment
BTG
Beacon Tracker Generator
BTL
Bell Telephone Laboratories (USA)
BTNA
Burst Timing Not Acquired
BTP
Burst Time Plan
BTPC
Burst Time Plan Change
BTPM
Burst Time Plan Memory
BTR
Beacon Tracker Receiver
BTS
Beacon Tracker System or Burst Timing Synchronization or Blockhouse Test Set
BTU
British Thermal Unit
BU
Baseband Unit
BUV
Backscatter Ultraviolet Spectrometer
BVU
Brightness Value Unit
BW
Bandwidth
BWR
Bandwidth Ratio
C
Capacitance or Capacitor or Coulomb
C-band
Used loosely for satellite services in the 6/4GHz bands or Used loosely for the frequency spectrum in the 3-7 GHz bands
C-MAC
Multiplexed Analog Component (TV, type C format)
C.T.T.
Emprêsa Pública dos Correios e Telecomunicaç es (Cape Verde)
C/D
ratio Charge/Discharge ratio
C/I
Carrier-to-Interference Ratio
C/IM3
Carrier-to-3rd Order Intermodulation Ratio
C/IMo
Carrier-to-Intermodulation Noise Density Ratio
C/N
Carrier-to-Noise Ratio
C/T
Carrier-to-Noise Temperature Ratio
C&D
Control and Display
C&DH
Control and Data Handling

Degrees Celsius or Degrees Centigrade
C2L
Close Complementary Logic
CAA
Crew Access Arm
CAD
Computer-Aided Design (or Drafting)
CADC
Control and Display Console
CAE
Computer-Aided Engineering
CAFS
Cape Canaveral AFS
CAL
Calibrate mode
CAM
Computer Aided Manufacturing
CAMA
Centralized Automatic Message Accounting
CAN
Cancel
CANTO
Caribbean Association of National Telecommunications Operators
CANTV
Compañía Anónima Nacional Teléfonos de Venezuela (Venezuela)
CAO
Completed As Ordered
CAP
Command Assistance Program
CAR
Channel Assignment Record
CAS
Collision Avoidance System or Commission for Atmospheric Sciences (WMO)
CASSA
Coarse Analog Sun Sensor Assembly
CAT
Computer Aided Tomography
CATH
Cathode
CATR
Compact Antenna (Test) Range
CATV
Cable Television or Community Antenna Television
CAW
Channel Address Word or Common Acquisition Window or Common Aerial Working
CAX
Community Automatic Exchange
CB
Citizens' Band (radio) (USA) or Clear Back or Common Battery
CBC
Canadian Broadcasting Corporation
CBCA
Constrained Beam Control Assignment
CBI
Conference Bridge In
CBS
Columbia Broadcasting System (USA)
CBTP
Condensed Burst Time Plan
CBTR
Carrier and Bit Timing Recovery
CC
Central Core or Closed Circuit or Common Carrier or Common Control
CCA
Collocated Communications Antenna
CCAFS
Cape Canaveral Airforce Station (USA)
CCAQ
Consultative Committee on Administrative Questions
CCB
Coin-Collecting Box
CCC
Control and Coordination Circuit
CCD
Charge Coupled Device
CCES
Common Control Echo Suppressor
CCI
(International Consultative Committee)
CCIF
(International Telephone Consultative Committee)
CCIR
Comite Consultatif International de Radio (International Radio Consultative Committee) (ITU) or International Radio Consultative Committee
CCITT
Comite Consultatif International des Telephones et Telegraphes (International Telephone and Telegraph Consultative Committee) (ITU) or International Telephone & Telegraph Consultative Committee
CCKF
Continuity Checktone Failure
CCP
Communications and Control Processor or Cross-Connection Point
CCS
Command Coordination System or Common Channel Signaling or Communication Coordination Station/System or Continuous Color Sequence
CCT
Circuit or Continuity Check Transceiver
CCTS
Coordinating Committee on Satellite Communications
CCTV
Closed Circuit Television
CCU
Central Control Unit
CCW
Counter-Clockwise
CD
Crystal Detector
CDA
Command and Data Acquisition (Station)
CDC
CCP Display Creation or Characteristic Distortion Compensation or Control & Delay Channel TDMA or Control and Delay Channel
CDD
Command Decryption Devices
CDE
Control and Display Equipment
CDF
Carrier Distribution Frame
CDHP
Command and Data Handling Package
CDM
Code Division Multiplex(ing) or Companded Delta Modulation
CDMA
Code Division Multiple Access
CDN
Content Delivery Network
CDR
Critical Design Review
CDRT
Central Data Recording Terminal
CEEFAX
Trade name for a videodata system (UK)
CELTIC
Names of French digital compression equipment for telephony
CEMA
Canadian Electrical Manufacturers Association (Canada)
CENTO
Central Treaty Organization
CENTROID
Center of thruster torque pulse
CEPT
(European Conference of Postal and Telecommunications Administrations) or Conference of European P&Ts
CES
Coast Earth Station (INMARSAT)
CESA
Canadian Engineering Standards Association
CEU
Command Extension Unit
CEVM
Consumable Electrode Vacuum Melt
CFDM
Companded Frequency Division Multiplex
CFDM/FM
Companded Frequency Division Multiplex/Frequency Modulation
CFE
Customer Furnished Equipment
CFM
Companded Frequency Modulation or Computer File Management System
CFN
Cluster Feeding Network
CFPA
C-band Full Performance Antenna
CFR
Code of Federal Regulations
CFRP
Carbon Fiber Reinforced Plastic
CG
Character Generator or Common Ground
CG OR cg
Center of Gravity
CG/MOI
Center of Gravity/Moment of Inertia
CGCI
Computer Generated Command Instruction
CGCIS
Computer Generated Command Instruction System
CGMS
Coordination of Geostationary Meteorological Satellites
CGPM
(General Conference of Weights and Measures)
CH
Channel
CHDB
Compatible High-Density Bipolar Code
CI
Command Interpreter or Configuration Item or Critical Item
CIC
Common Interface Circuit or Cover Integrated Cell
CID
Cathode Imaging Detector or Charge Injection Device
CIESPAL
Centro Internacional de Estudios Superiores de Comunicación para América Latina (International Center of Advanced Communication Studies for Latin America)
CIFAS
French-German Industrial Consortium for Symphonie Program
CIGRE
(International Conference on Large Electric Systems)
CIMS
Coordination & Interference Management System
CIRC
International Radiomaritime Committee
CIRM
International Marine Radio Association
CISPR
(International Special Committee on Radio Interference)
CITE
Cargo Integrated Test Equipment
CITEL
Inter-American Telecommunications Committee
CKE
Zero Kinetic Energy
CKR
Receive Bit Clock
CKT
Transmit Bit Clock
CL
Closed or Closed Loop
CLD
Command Logic Demodulators
CLE
Common Logic Equipment
CLI
Calling Line Identification
CLK
Clock
CLR
Clear
cm OR CM
cm Centimeter or CM Command Module or CM Configuration Management
cm²
Square centimeter
CMC
Central Monitoring and Control
cmd OR CMD
Command
CMDR
Command Rejected
CME
Circuit Multiplication Equipment
CME/LRE
Circuit Multiplication/Low Rate Encoding Equipment
CMEA
Council on Mutual Economic Assistance
CMG
Control-Moment Gyroscope
CMI
Code Mark Inversion
CML
Current-Mode Logic
CMOS
Complementary Metal Oxide Semiconductor/Silicon
CMR
Common-Mode Rejection
CMRR
Common-Mode Rejection Ratio
CMSA
Consolidated Metropolitan Statistical Area
CMT
Continuous Mode Transmission
CMTT
(Joint Study Group for Television and Sound Transmissions)
CMU
Command Modulation Unit
CN
Check Not-Okay
CNES
Centre National d'Etudes Spatiales (France)
CNET
Centre National d'Etudes des Télécommunications (France)
CNIE
Comisión Nacional de Investigación del Espacio (Argentina)
CNR
Carrier-to-Thermal-Noise Ratio or Consiglio Nazionale Delle Richerche (Italy)
CNSS
Center for National Space Study
CO
Central Office or Check Okay or Circuit Order or Crystal Oscillator
CO-ORD
Coordination Channel
Coax
Coaxial Cable
COBOL
Common Business-Oriented Language
CODAN
Carrier Operated Device Anti-Noise
Codec OR CODEC
Coder-Decoder
COHO
Coherent Oscillator
COM
Computer Output Microfilm
COMSAT
Communications Satellite Corporation
COMTELCA
Comisión Técnica de Telecomunicaciones de Centroamérica (Commission of Technical Telecommunications of Central America)
CONDOR
Satellite Network of the Andean Group
CONG
Congestion Error Control
CONT
Controller
CONUS
Continental United States (Coverage)
COP
Communications Operation Plan
COPOL OR CO-POL
Co-Polarization
COPS
Command Operations
COPSK
Coded Octal Phase Shift Keying
COPUOS
Committee on the Peaceful Uses of Outer Space (UN)
COR
Carrier-Operated Relay
CORODIM
Correlation of the Recognition of Degradation With Intelligibility Measurements
CORSA
Cosmic Radiation Satellite (Japan)
COS
Characteristic Orbital Spacing
COSAM
Co-Site Analytical Model
COSMOS
Military Satellite Network (Russian Federation)
COSPAR
Comité Mondial de la Recherche Spatiale (World Committee on Space Research) (ICSU-UN)
COSTED
Committee on Science and Technology in Developing Countries (ICSU-UN)
COTS
Commercial-off-the-Shelf
CP
Circular Polarization
CPA
Co-Polar Attenuation
CPC
Clock Phase Correction
CPCC
Clock Phase Correction Control
CPE
Customer Premise Equipment
CPFSK
Continuous Phase Frequency Shift Keying
CPI
Call Progress Indicator
CPLF
Clock Phase Log File
CPM
Coded-Phase Modulation or Communications Payload Monitoring or Critical Path Method
CPPI
Consultative Panel on Public Information (UN)
CPRI
Clock Phase Reporting Interval
cps OR CPS
Cycles Per Second
CPSK
Coherent Phase-Shifting Key
CPU
Central Processing Unit
CPVE
Clock Phase Value Entry
CQ
Call "To All Stations"
CQPSK
Quaternary Phase-Shift Keying with Coherent Demodulation
CR
Carriage Return or Carrier Recovery or Cathode Ray or Encoding change|Reassignment procedure
CRA
Centro Ricerche Aerospaziali (Italy)
CRAN
Command Receive Antenna
CRBW
Carson Rule Bandwidth
CRC
Communications Research Center (Canada) or Cyclic Redundancy Code
CRD
Chord
CRDM/F
Companded Frequency Division Multiplex/Frequency
CRO
Cathode Ray Oscilloscope (or Oscillograph) or Central Radio Office
CROM
Control and Read-Only Memory
CRPL
Central Radio Propagation Laboratory (USA)
CRQ
Call Request
CRRES
Combined Release and Radiation Effects Satellite(combined NASA/USAF Mission - USA)
CRT
Cathode Ray Tube
CRTO
Centre Rigionali (Italy)
CRYO
Cryogenic
CS
Calls per Second or Currency Sign
CSC
Common Signaling Channel or Computer Sciences Corporation Inc.
CSCD
Common Signaling Channel Demodulator
CSCE
Communications Subsystem Checkout Equipment
CSCM
Common Signaling Channel Modem
CSCS
Common Signaling Channel Synchronizer
CSE
Communications Satellite for Experimental Purposes (Japan)
CSELT
Centro Studi e Laboratori Telecomunicazione (Italy)
CSG
Centre Spatial Guyanais (Guiana Space Center)
CSM
Communications System Monitor
CSM/CSME
Communications Systems Monitor(ing)/Equipment
CSME
CSM Equipment
CSOC
Consolidated Space Operations Center
CSSB
Companded Single Sideband
CSTD
Committee on Science and Technology for Development
CSU
Channel Service unit or Check Signal unit or Constant Speed Unit
CSW
Channel Status Word
CT
Center Tap or Transit Center (Centre du Transit) (international telephones)
CTC
Common Telegraphy Channel or Communications, Telemetry and Command
CTCA
Constrained Terminal Control Assignment or Constrained Terminal Control Assignment SSTDMA
CTE
Channel Translating Equipment or Coefficient of Thermal Expansion
CTL
Control
CTP
Command and Telemetry Processor or Condensed Burst Time Plan
CTR
Configuration Track Record
CTTE
Common TDMA Terminal Equipment
CTU
Central Telemetry Unit or Characterization Test Unit
CU
Crosstalk Unit
CUC
Computer Users' Committee
CVA
Constant Volume Amplifier or Control Voltage Alternator
CVD
Chemical-Vapor Phase Deposition
CVM
Command Verification Module
CVSD
Continuous Variable Slope
CVSDM
Continuously Variable-Slope Delta Modulation
CW
Carrier Wave or Clockwise or Continuous Wave
CWBS
Contract Work Breakdown Structure
CX
Coin Box
CXR
Carrier
D-MAC
Multiplexed Analog Component (TV, type D format)
D.A.T.E.
Duly Authorized Telecommunications Entity
d.p.
Drip-Proof
D/
Diameter/wavelength ratio
D/A
Digital to Analog
D/C
Downconverter
D/L
Downlink
D2-MAC
Multiplexed Analog Component (TV, type D2 format)
DA
Demand Assignment or Differential Absorption
DAC
Digital to Analog Converter
DACCS
Digital Access Cross-Connect System
DAIT
Demand Assigned International Terminal
DAMA
Demand Assigned Multiple Access or Demand Assignment Multiple Access
DAND
Despin Active Nutation Damper or Despin Torque Actuated Nutation
DASCPC/QPSK
Demand Assigned Single-Channel-Per-Carrier/Quadrature Phase Shift Keying
DASS
Demand Assignment Signaling and Switching Unit
DATE
Duly Authorized Telecommunications Entity
DATTS
Data Acquisition Telecommand and Tracking Station
DAV
Data-Above-Voice
DAVC
Delayed Automatic Volume Control
dB OR DB
Decibel or Dry Bulb
dB/K
Decibels per Degree Kelvin
dBC
C-scale Sound Level in Decibels
dBm
Decibels Relative to one Milliwatt
dBm0
dBm referred to or measured at a point of zero transmission level(0TLP)
dBm0p
dBm Point psophometrically weighted referred to or measured at a point of zero transmission level (0TLP)
DBMS
Data Base Management System
DBP
Deutsche Bundepost (Germany)
DBS
Direct Broadcast Satellites
DBTR
Digital Bit Timing Recovery
dBV
Decibels Above 1 Volt
dBW
Decibels relative to one Watt
DC OR d.c.
DC Directional Coupler or DC Down Converter or DC OR d.c. Direct Current
DC/DC
Direct Current to Direct Current
DCA
Defense Communications Agency (USA)
DCC
Demand Assignment Call Connect
DCCC
Double-Current Cable Code
DCD
Data Carrier Detector or Demand Assignment Call Disconnect
DCDR
Data Collection and Data Relay
DCE
Data Communications Equipment Data Circuit Terminating Equipment or Despin/Despun Control Electronics or Digital Communications Equipment (Timeplex)
DCM
Device Control Management
DCME
Digital Circuit Multiplication Equipment
DCME/DCMS
Digital Circuit Multiplication Equipment/System
DCN
Document Change Notice
DCP
Data Collection Platform
DCPSK
Differentially Coherent Phase Shift Keying
DCR
Document Change Request
DCRT
Data Collection Receive Terminal
DCS
Data Collection System or Data Communications Service or Despin Control Subsystem or Direct Couple System or Dual Channel Synchronizing
DCTL
Direct-Coupled Transistor Logic
DCTV
Despin Compartment Thermal Vacuum Test
DCU
Data Concentrator Unit or Display and Control Unit or Distribution and Control Unit
DD/C
Dual Downconverter
DDC
Double Downconverter
DDD
Direct Distance Dialling
DDF
Digital Distribution Frame
DDI
Direct Digital Interface
DDIE
Direct Digital Interface Equipment
DDP
Digital Data Processor
DDS
Digital Data System
DEC
Declination
DEF
Defined
DELTA
Launcher (McDonnell Douglas - USA)
Delta-P
Pressure Difference
Demod
Demodulator
Demux OR DEMUX
Demultiplexer
DES
Digital Encryption Standard
DET
Detector
DEV
Deviation
DF
Direction Finding or Distribution Frame
DFS
Domestic satellite network (Germany)
DG
Differential Gain or Director General
DGL
Device Independent Graphics Library
diac
Diode AC Switch
DID
Direct Inward Dialling
DIOS
Digital In-band Open-Look Synchronization
DIP
Dual In-line Package
DIRA
Digital Integrating Rate Assembly
DIRT
Decide-In-Real-Time commanding
DISC
Disconnect command
DITEC
Digital Television Communication System
DIUR
Diurrnal
DIV
Data-In-Voice
DLC
Data Link Receive (Timeplex) or Dynamic Load Control
DLE
Data Link Escape
DLF
Direct Through-Connection Filter
DM
Delta Modulation or Discriminator
DM/PSK
Delta Modulation/Phase Shift Keyed
DMA
Direct Memory Access or Dynamic Memory Allocation
DME
Distance Measuring Equipment
DMM
Digital Multimeter
DMSP
Defense Meteorological Satellite Program (USA)
DNI
Digital Non-Interpolated
DNIC
Data Network Identification Code
DNTX
Do Not Transmit
DOC
Digital Operations Center
DOD
Department of Defense (USA) or Depth of Discharge
DOM
Domestic
DOMP
Distributed Orbital Mechanical Process
DOMSAT
Domestic Satellite System
DOPSK
Differential Offset Phase Shift Keying
DOS
Disk Operating System
DOV
Data-Over-Voice
DOVAP
Doppler Velocity and Position
DP
Differential Phase or Display Processor or Distribution Point
DPA
Destructive Physical Analysis
DPC
Data Processing Center
DPCM
Differential Pulse Code Modulation
DPDT
Double Pole Double Throw (switch)
DPL
Deployed
DPM
Digital Panel Meter
DPSK
Differential Phase Shift Keyed
DPST
Double Pole Single Throw (switch)
DPTC
Digital Program Track Controller
DPU
Data Processing Unit
DQPSK
Differential Quadrature PSK
DR
Data Rate or Dynamic Range
DRE
Directional Reservation Equipment
DRGS
Direct Readout Ground Station
DRL
Contract Data Requirements List
DRO
Dielectric Resonator Oscillators
DRP
Directional Radiated Power
DRS
Direct Reception Station
DRT
Data Recording Terminal
DS
Data Speech or Degraded Seconds or Direct Sequence or Link Processor's Outgoing Message program
DS-3
Digital Signal 3
DS1, etc.
Digital Services
DSB
Direct Sounding Broadcast or Double Sideband
DSB-SC-AM
Double Sideband-Suppressed Carrier-Amplitude Modulation
DSB-SC-AM w/QM
Double Sideband-Suppressed Carrier-Amplitude Modulation with Quadrature Multiplexing
DSB-SC-ASK
Double Sideband-Suppressed Carrier-Amplitude Shift Keyed
DSCS
Defense Satellite Communications System (USA)
DSDU
Despun Squib Driver Unit
DSE
Data Switching Exchange
DSI
Digital Speech Interpolation
DSI-AC
Digital Speech Interpolation Assignment Channel
DSIP
DS Interface Package
DSL
Deep Scattering Layer
DSM
Dual Synchronous Module
DSMDU
Despun Stepper Motor Driver Unit
DSN
Domestic satellite network (Israel)
DSP
Define Switch Parameter (Timeplex)
DSR
Data Set Ready
DSS
Digital Sun Sensor or Downlink Selector Switch
DST
Direct Sounding Transmission
DSU
Disk Storage Unit
DTC
Detection Threshold Computer
DTE
Data Terminal Equipment or Digital Transmission Equipment (Timeplex)
DTI
Data Transfer Interface
DTL
Diode-Transistor Logic
DTM
Digital Termination Module to Dynamic Transfer Mode
DTMF
Dual Tone Multiple Frequency
DTP
Detailed Test Plan
DTR
Down-Time Ratio
DUC
Double Upconverter
DUS
Data Utilization/User Station
DUT
Device Under Test
DUV
Data Under Voice to Digital Under Voice
DVLP
Development Center (Intelsat's)
DVM
Digital Volt Meter
DVT
Design Verification Test
DWN
Down
DX or dx
DX Distance reception or dx Duplex
e.i.r.p.
EIRP Equivalent Isotropically Radiated Power
e.m.r.p,
Effective Monopole-Radiated Power
e.r.p.
Effective Radiated Power
E/A
Events and Alarms subsystem
E/Q
Energy per Unit Charge
E/S
Earth Station or Lib PT Earth/Sun Liberation Point
E/W
East/West
EAC
Engineering Assistance Contract
EAGE
Electrical Aerospace Ground Equipment
EAROM
Electrically-Alterable ROM
EAS
Events and Alarms System or Extended Area Service
Eb/No
Energy per Bit to Noise density ratio
EBCDIC
Extended Binary-coded Decimal Interchange Code
EBHC
Equated Busy Hour Call
EBR
Electronic Beam Recorder
EBU
European Broadcasting Union
EC
Earth Chord or Echo Canceler or Engineering Channel
ECA
Earth Chord measured from earth sensor A or Economic Commission for Africa
ECB
Earth Chord measured from earth sensor B
ECC
Eccentricity
ECD
Echo Control Device
ECE
Economic Commission for Europe
ECH
Earth Coverage Horn
ECL
Emitter Coupled Logic
ECLA
Economic Commission for Latin America
ECM
Error Correction Mode
ECMA
European Computer Manufacturers Association
ECO
Electron-Coupled Oscillator
ECOM
Electronic Computer-Originated Mail
ECR
Earth Centered Rotating
ECRA
Electrical Contact Ring Assembly
ECS
European Regional Communications Satellite System or Experimental Communications Satellite (Japan)
ECU
Electrical Conversion Unit
ECWA
Economic Commission for Western Asia
EDA
Electronic Despun Antenna
EDC
Effective Date of Contract or Error Detection and Correction subsystem
EDF
Energy Dispersal Function
EDI
Electronic Data Interchange
EDOR
Early Definition of Requirements
EDP
Electronic Data Processing
EDPM
Electronic Data Processing Machine
EDPS
Experiment Data and Power System
EDTV
Enhanced Definition Television
EDW
Energy Dispersion Waveform
EEA
Electrostatic Energy Analyzer
EFdS
Error Free Deciseconds
EFI
Error-Free Intervals
EFS
Error-Free Seconds
EFT
Electronic Funds Transfer
EFTA
European Free Trade Association
EG/No
Energy per bit to Noise Density Ratio
EHF
Extremely High Frequency (Miriametric waves)
EIA
Electronic Industries Association (USA)
EIRESAT
Satellite network (Ireland)
EISCAT
European Institute Scatter Facility
EJ
Electronic Journalism
EJF
Estimated Junction Frequency
EKRAN
Statsionar Satellite (Russian Federation)
EL
Elevation
ELEA
Earth Leading Edge A
ELEB
Earth Leading Edge B
ELF
Extremely Low Frequency
ELT
Emergency Locater Transmitter
ELU
Existing Carrier Line-Up
ELV
Expendable Launch Vehicles
EM
Electromagnetism or Engineering Model
EMA
Extended Memory Access
EMBRATE
Emprêsa Brasileira de Telecomunicaç es S.A. (Brazil)
EMC
Electromagnetic Compatibility
EMC FOM
Electromagnetic Compatibility Figure of Merit
EME
Earth-Moon-Earth
EMF
Electromagnetic Force or Electromotive Force
EMI
Electromagnetic Interference
Emin
Minimum Usable Field Strength
EMP
Electromagnetic Pulse
EMS
Electronic Message Service
EMU
Extra-vehicular Maneuvering Unit
ENA
Enabled
ENC
Encoding unit control process
ENG
Electronic News Gathering
Enom
Nominal Usable Field Strength
ENTEL
Empresa Nacional de Telecomunicaciones S.A. (Bolivia), (Chile),(Peru)
ENV
Envelope
EOC
Edge of Coverage
EOD
End of Dialling
EOL
End Of Life
EOOS
Early Orbit Operations Services (Intelsat)
EOS
Earth Observation Satellite or End Of Service
EOW
Engineering Order Wire
EPC
Electronic Power Conditioner/Converter
EPDS
Experiment Power and Data Systems
EPI
Elevation Position Indicator
EPIRB
Emergency Position Indicating Radio Beacon
EPROM
Erasable PROM
EPTEL
Emprêsa Pública de Telecomunica es (Angola)
EQM
Engineering Qualification Model
ER&S
Exploratory Research and Studies
ERB
Earth Radiation Budget
ERBE
Earth Radiation Budget Experiment
ERL
Echo Return Loss
EROS
Earth Resources Observation Satellite (USA)
ERP
Effective Radiated Power
ERR
Error
ERS
Earth Resources Satellite or Enhanced Roving Spot or Environmental Research Satellite (USA) or ESA Remote Sensing Satellite
ERSOS
Earth Resource Survey Operational System
ERTS
Earth Resources Technology Satellite (USA)
ERU
Encoding Rate Update
Es or ES
Es (sporadic E) or ES Echo Suppressor or ES Errored Second
ESA
Earth Station Antenna or European Space Agency
ESC
Engineering Service Circuit/Channel or Escape or European Space Conference or Exhaust
ESCAP
Economic and Social Commission for Asia and the Pacific
ESCES
Environmental Satellite Communication Earth Station (India) or Experimental Space Communication Earth Station
ESD
Electrostatic Discharge
ESM
Eastern Space and Missile Center
ESMR
Electrically Scanning Microwave Radiometer
ESOC
European Space Operations Center
ESPA
Earth Sensor Processor Electronics Package A
ESPB
Earth Sensor Processor Electronics Package B
ESPE
Earth Sensor Processing Electronics
ESRANGE
European Sounding Rocket Landing Range (ESA)
ESRO
European Space Research Organization
ESS
Electronic Switching System
ESSA
Environmental Survey Satellite
EST
Estimate
ESTEC
European Space Research and Technology Center
ESU
Empty Signal Unit
ETA
Estimated Time of Arrival
ETD
Estimated Time of Departure
ETF
Error Threshold Firing
Ethernet
A family of frame-based computer networking technologies for local area networks (LANs).
ETS
Electronic Translator System or Engineering Test Satellite (Japan)
ETSI
European Telecommunication Standards Institute
ETT
Electrothermal Thrusters
ETV
Educational Television
EU OR Eu
EU Engineering Unit or Eu Usable Field Strength
EUMETSAT
European Organization for the Exploration of Meteorological Satellites
EURECA
European Retrievable Carrier (Spacecraft)
EUROCONTROL
European Organization for Safety of Air Navigation
EURONET
European Public Network (Data)
EUROSAT
Organization to implement a European system of telecommunications and TV by satellite
EUROSPACE
European Industrial Space Study Group
EUROVISION
European and Mediterranean TV services
EUTELSAT
European Telecommunications Satellite Organization
EUV
Extreme Ultraviolet
EUVE
Extreme Ultraviolet Explorer (NASA Satellite)
eV
Electron Volt
EVA
Extra-Vehicular Activity
EVR
Electronic Video Recording
EW
Electronic Warfare
EXCLUSIVE-NOR
Type of Logic Circuit
EXCLUSIVE-OR
Type of Logic Circuit
EXOS
Exospheric Satellite (Japan)
EXOSAT
European X-Ray Observation Satellite (ESA)
EZ
Ephemeris Time
F
Farad or Microfarad
F/D
Focal Length to Diameter Ratio
f/o
Fiber Optic
F/V
Frequency-to-Voltage

Degree Fahrenheit
FACC
Ford Aerospace & Communications Corporation
FACT
Fabrication And Continuity Test Program
FAS
Frame Acquisition and Synchronization
FAX
Facsimile
FBSS
Full Band Spread Spectrum
FC or Fc
FC Forecast Center Station or Fc Sampling Frequency
FCC
Federal Communications Commission (USA)
FCD
Facility Completion Date
FCS
Frame Check(ing) Sequence
FD
Functional Description
FD-PSK
Frequency Differential Phase-Shift Keyed System
FDB
Fahrenheit Dry Bulb or Functional Description Block
FDC
Flight Dynamics and Commanding
FDFM
Frequency Division/Frequency Modulation
FDM
Frequency Division (or Domain) Multiplex
FDM/CFM
Frequency Division Multiplex/Companded
FDM/FM
Frequency Division Multiplex/Frequency Modulation
FDMA
Frequency Division Multiple Access
FDR
Final Design Review
FDS
Flight Dynamic System
FDSS
Fine Digital Sun Sensor
FDSSA
Fine Digital Sun Sensor Assembly
FDSSE
Fine Digital Sun Sensor Electronics
FE
Fast Ethernet or Format Effector
FEC
Forward Error Correction
FET
Field Effect Transistor
FF
Flip Flop (bistable electronic circuit)
FFC
Feed Forward Compensation
FFP
Firm Fixed Price or Fixed Fee Procurement
FFT
Fast Fourier Transform
FGGE
First GARP Global Experiment
FH
Frequency Hopping
FIFO
First In-First Out
FIL
Filter
FINTEL
Fiji International Telecommunications Limited (Fiji)
FIR
Flight Information Region
FIS
Flight Information Service
FIT
Failure in Time
FITE
Forward Interworking Telephony Event
FITS
Failures in 109 hours
FL
Fuel
FLS
Free Line Signal
FLTR
Filter
FLTSATCOM
US Navy Satellite Communications System (USA)
FLU
Full Line Up
FLV
Fuel Valve
FM
Frequency Modulation
FM/FDMA
Frequency Modulation/Frequency Division Multiple Access
FMA
Ferrite Modular Assembly
FMC
Fallback Master Clock
FMEA
Failure Modes and Effects Analysis
FMECA
Failure Modes, Effects, and Criticality Analysis
FMFB
Frequency Modulation Feedback
FMVT
Frequency Modulation Voice Telegraphy
FMW
Fixed Momentum Wheel
FMWA
Fixed Momentum Wheel Assembly
FOM
Factor of Merit
FORTRAN
Formula Translation
FOS
Follow-On Satellite (Intelsat)
FOT
Optimum Working Frequency
FOV
Field of View
FP
Full Period
FPA
Final Power Amplifier or Full Performance Antenna
FPR
Flat Plate Radiometer
FRMR
Frame Rejected
FRR
Fast Reroute or First (right of) Refusal Reservations or Flight Readiness Review
FRS
Forward Ready Signal
FRU
Field Replaceable Unit
FRXD
Fully Automatic Reperforator Transmitter Distributor
FS
Figure Shift or File Separator or Fixed Service or Frequency Shift or Full-Scale or Functional Specialization
FSB
Frame Synchronizer and Buffer or Functional Specification Block
FSD
Full-Scale Deflection
FSF
Fading Safety Factor
FSK
Frequency Shift Keying
FSS
Fixed Satellite Service or Flight Support System
FT
Foot (unit of measure) or Forward Transfer
FT/MIN
Foot per Minute
FT/S
Foot per Second
FT²
Foot Squared
FTF
Fixed Time Firing
FTP
File Transfer Protocol
FUL
Fuel
FVDA
Fully Variable Demand Access
FWB
Fahrenheit Wet Bulb
FWD
Forward or front
G
Gain or Giga (109) or Gravity
G-M tube
Geiger-Mueller tube
G/T
Gain to Noise Temperature Ratio or Gain-over-Temperature
GaAs
Gallium Arsenide
GaAsFET
Gallium Arsenide Field Effect Transistor
GAGR
Group Automatic Gain Regulator
GALAXY
Domestic Satellite (Hughes Communications - USA)
GARP
Global Atmospheric Research Program
GARS
Geological Applications for Remote Sensing
GAS
Special Autonomous Study Group (I.T.U.)
GATT
General Agreement on Tariffs and Trade
GbE OR GigE
Gigabit Ethernet
GCE
General Certificate of Education (UK) or Ground Communications Equipment
GCS
Ground Control System
GDF
Group Distribution Frame
GDL
Satellite System (Luxembourg)
GDMO
General Definition of Managed Objects
GDN
Graphic Display Network
GDP
Gross Domestic Product
GDPS
Global Data Processing System (WMO)
GE
General Electric (USA)
GEMS
Global Environment Monitoring System (UN)
GEO
Geosynchronous (geostationary) Equatorial Orbit
GEO-IRS OR GEOIRS
Geostationary Orbit Infrared Sensor
GEOS
Geodetic Earth-Orbiting Satellites (NASA) or Geostationary earth Orbiting Satellite (ESA, USA)
GEU
Ground Encryption Unit
GFE
Government Furnished Equipment
GFRP
Graphite or Glass Fiber Reinforced Plastic
GGSE
Gravity Gradient Stabilization Experiment Satellite (USA)
GGTS
Gravity Gradient Test Satellite
GHA
Greenwich Hour Angle
GHIUD
Global Human Information Use Per Decade
GHz
Gigahertz (1 billion cycles per second)
GIP
Group Interface Processor
GLB
Global antenna
GM
Gravitational parameter
GMA
Gated Mode Acquisition
GMC
General Motors Corporation
GME
Group Modulating Equipment
GMS
Geostationary Meteorological Satellite or Geostationary Meteorological Satellite (Japan)
GMT
Greenwich Mean Time
GN
Gain
GNC
Ground Nutation Controller
GND
Ground/Earth
GOES
Geosynchronous Operational Environmental Satellite (USA)
GORC
Global Operations Representative Conference
Gorizont
Communication Satellite (Russian Federation)
GOS
Global Observing System (WMO)
GP OR Gp
GP General Processor or Gp Group
GPC
General Purpose Computer
gpDm
Geopotential Decameter (1 ghDm = 9,81m)
GPIB
General Purpose Interface Bus
GPS
Global Positioning Satellite/System (US)
GRARR
Goddard Range and Range Rate (USA)
GRD
Ground Resolved Distance
GRFP
Graphite-Fiber-Reinforced Plastic
GRGS
(Space Geodesy Research Group)
GRID
Global Resource Information Database
GRND
Ground
GRP
Group or Group Reference Pilot/Point
grt
Gross Registered Tons
GS
Group Separator
GSB
Global Storage Block
GSE
Ground Support Equipment
GSFC
Goddard Space Flight Center (USA)
GSO
Geostationary Satellite Orbit
GSTAR
Domestic Satellite Network (Owned by GTE Satellite Corporation - USA)
GTE
General Telephone & Electronics, Inc. (USA) or Group Translating Equipment
GTM
Global Traffic Meeting (Intelsat)
GTO
Geostationary (or geosynchronous) Transfer Orbit
GTS
Global Telecommunications System (WMO)
GUATEL
Empresa Guatemalteca de Telecomunicaciones (Guatemala)
GUI
Graphical User Interface
GWN
Gaussian White Noise
H
Microhenry
HAC
Hughes Aircraft Company (USA)
HAD
Half Amplitude Duration
HAKUCHO
Cosmic Radiation Satellite (same as CORSA) (Japan)
HCE
Heater Control Electronics
HD
High Definition
HD-SDI
High Definition-Serial Digital InterfaceHigh Definition
HDB
High Density Bipolar Code
HDLC
High Level Data Link Control
HDRSS
High Data Rate Storage System
HDTV
High Definition Television
HDX
Half Duplex (syn.: semi-duplex)
HE
Heat Exchanger
HEAO
High-Energy Astronomy Observatory
HELIOS
Experimental Satellite (Germany)
HELVESAT
Broadcast Satellite System (Switzerland)
HEM
Hughes Engineering Module
HEMT
High Electron Mobility Transistors
HEOS
Highly Eccentric Orbit Satellite
HF
High Frequency (3,000 - 30,000 Khz)
HILAT
High Latitude Satellite (DOD - USA)
HIRS
High Resolution Infrared Sounder
HISPASAT
Satellite Network (Spain)
HL
Half-Life (radioactive)
HLL
High-Level Language
HLLV
Heavy Lift Launch Vehicle
HLX
Helix
HM
Hybrid Modulation
HNS
Hughes Network Systems
HONDUTEL
Empresa Hondureña de Telecomunicaciones (Honduras)
hp OR HP
HP Hewlett-Packard (company, USA) or hp OR HP Horsepower
HPA
High Power Amplifier
HPBW
Half-Power Beam Width
HPF
Hazardous Processing Facility or High Pass Filter
HPI
Height Position Indicator
HPIB
Hewlett Packard Interface Board
HPM
Hybrid Phase Modulation
HQ
Intelsat Headquarters
HQES
Headquarters Earth Station
HRC
Hypothetical Reference Circuit
HRDC
Hypothetical Reference Digital Circuit
HRDP
Hypothetical Reference Digital Path
HRFAX
High Resolution Facsimile
HRIR
High Resolution Infrared Scanning System
HRP
Historical Storage and Retrieval Processor
HRX
Hypothetical Reference Connection
HSE
Host Station Equipment
HT
Horizontal Tabulation
HTR
Heater
HV
High Voltage
HVM
High Voltage Module
HW
Hardware
HYPACE
Hybrid Programmable Attitude Control Electronics
Hz
Hertz (Cycles per Second)
I/O
Input/Output
I&D
Integrate and Dump Detection
IAAB
Inter-American Association of Broadcasting
IAE
AInternational Atomic Energy Agency
IAF
International Astronautical Federation
IAGA
International Association of Geomagnetism and Aeronomy
IAGC
Instantaneous Automatic Gain Control
IAI
Initial Address Information
IAP
Initial Acquisition Phase
IARU
International Amateur Radio Union
IAT
Intermediate Attitude Trim or International Atomic Time
IATA
International Air Transport Association
IATE
International Accounting and Traffic Analysis Equipment
IAU
International Astronomical Union
IB
Input Buffer
IBC
Interface Buffer Controller or Internal Bus Controller
IBI
Intergovernmental Bureau for Informatics or International Broadcast Institute
IBRD
International Bank for Reconstruction and Development (World Bank)
IBS
Intelsat Business Services
IBS/FT
Intelsat Business Service Full Time
IBTO
International Broadcasting and Television Organization
IC
Index Correction or Integrated Circuit or International Channel
ICAO
International Civil Aviation Organization
ICB
Incoming Call Barred
ICC
Intelsat Communications Center or International Chamber of Commerce or International Communications Conference
ICDSC
International Conference on Digital Satellite Communications
ICI
International Commission on Illumination
ICN
Idle Channel Noise or In-band Channel Noise
ICON
Intelsat Information and Communications Network
ICPO
International Criminal Police Organization (Interpol)
ICRP
International Commission on Radiological Protection
ICS
International Chamber of Shipping
ICSA
Intelsat Computer Systems Architecture document
ICSAB
International Civil Service Advisory Board
ICSU
International Council of Scientific Unions
ICW
Interrupted Carrier Wave or Interrupted Continuous Wave
ID
Identification or Identifier
IDA
International Development Association
IDB
Integrated Data Base
IDC
Image Dissector Camera or International Digital Communications (Japan)
IDCC
International Data Communications Center or International Data Coordinating Center
IDCP
International Data Collecting Platform
IDDD
International Direct Distance Dialing
IDF
Intermediate Distribution Frame
IDN
Integrated Digital Network or Integration Development Notebook
IDP
Integrated Data Processing
IDR
Intermediate Data Rate
IDTV
Improved Definition TV
IE
Index Error or Intelsat Engineer
IEA
International Energy Agency
IEC
International Electrotechnical Commission
IEE
Institute of Electrical Engineers (UK)
IEEE
Institute of Electrical and Electronic Engineers (USA)
IEEIE
Institute of Electrical and Electronic Incorporated Engineers
IERE
Institution of Electronics and Radio Engineers
IES
Incoming Echo Suppressor
IESS
Intelsat Earth Station Standards
IETEL
Instituto Ecuatoriano de Telecomunicaciones (Ecuador)
IEU
Interface Electronics Unit
IEV
International Electrotechnical Vocabulary
IF
Intermediate Frequency
IFA
Intermediate Frequency Amplifier
IFD
In-Flight Disconnects
IFE
Intelsat Furnished Equipment
IFF
Intensity Fluctuation Factor
IFIP
International Federation for Information Processing
IFL
Inter-Facility Link or International Frequency List (List I)
IFOV
Instantaneous Field of View
IFR
Instrument Flight Rules
IFRB
International Frequency Registration Board (ITU)
IFS
Intelsat Financial System or Investment Feasibility Studies
IFTC
International Film and Television Council
IGFET
Insulated-Gate Field Effect Transistor
IGOSS
Integrated Global Ocean Station System
IGRF
International Geomagnetic Reference Field
IIC
Individual Interactive Commanding or International Institute of Communications
IICM
Intelsat Intersystem Coordination Manual
IISL
International Institute of Space Law
ILC
Inter-Link Controller (Timeplex Card)
ILD
Injection Laser Diode
ILS
Integrated Logistical Support
IM
Intelsat Management or Intermodulation
IMC
International Maintenance Center
IMD
Intermodulation Distortion
IMMED
Immediate
IMO
International Maritime Organization (formerly IMCO)
IMP
Interface Message Processor or Interplanetary Monitoring Platform (NASA Satellite - USA)
IMPATT
Impact Avalanche Transit Time (diode)
IMPD
Impedance
IMUX
Input Multiplexer
in/s
Inches per second
in²
Square inch
INAG
Ionospheric Network Advisory Group
INC
Inclination
INCATEL
Instituto Centroamericano de Telecomunicaciones (Central American Institute of Telecommunications)
INJ
Injector
INMARSAT
International Maritime Satellite Organization
INSAT
Domestic Satellite Network (India)
INTEL
Instituto Nacional de Telecomunicaciones (Panama)
INTELCAM
Société des Télécommunications Internationales du Cameroun (Cameroon)
INTELCI
Société des Télécommunications Internationales de Côte d'Ivoire (Ivory Coast)
INTELCO
Office des Télécommunications Internationales du Congo (Congo)
INTELPOST
Name of international organization created to conduct experimental electronic mail transmissions
INTELSAT
International Telecommunications Satellite Organization
INTERCOMSA
Intercontinental de Comunicaciones por Satélite, S.A. (Panama)
INTERCOSMOS
International Research Satellites (Russian Federation)
INTERSPUTNIK
International Space Telecommunication Organization (Russian Federation)
INUKSAT
Domestic Satellite System (proposed by Denmark)
IOB
Inter-Organization Board for Information Systems and Related Activities
IOC
Input/Output Controller or Intelsat Operations Center
IOCTF
Intelsat Operations Center TDMA Facility
IOO
Inclined Orbit Operation
IOR
Indian Ocean Region
IOT
In-Orbit Test
IOTA
Intelsat Online Transaction Access
IOTE
In-Orbit Test Equipment
IP
Index Pulse or Input Processor or Internet Protocol
IPA
Intermediate Power Amplifier
IPCE
Interface Power Conditioning Electronics
IPDC
International Program for Development of Communications
IPG
Index Pulse Generator
IPP
International Phototelegraph Position
IPS
Input Processing and Service request generation block or Instrument Pointing System or Integrated Planning System or Ion Propulsion Subsystem or Ionospheric Prediction Services
IPTC
International Press Telecommunications Council
IPU
Information Processing Ability
IR
Information Rate or Infrared
IRB
Inoperative Reference Burst
IRE
Institute of Radio Engineers
IRIG
Inter-Range Instrumentation Group
IRLS
Interrogation, Recording and Location System
IRP
International Routing Plan
IRS
Information Receiving Station or Intermediate Reference System
IRTV
Infra-Red Thermal Vacuum
IRU
Indefeasible Right of Use or Inertial Reference Unit
IS
Information Separator
ISAS
Institute of Space and Aeronautical Science (Japan)
ISB
Independent Side Band
ISC
Intelsat Service Center or Interdisciplinary Scientific Commission (COSPAR) or International Switching Center
ISCC
International Service Coordination Center or Intelsat Satellite Control Center (see SCC)
ISCOM
Satellite for Communication Technology (India)
ISCS
Integrated Satellite Conrol Systems
ISEE
International Sun-Earth Explorers
ISF
International Shipping Federation
ISIS
International Satellite for Ionospheric Studies (USA/Canada)
ISL
Inter Satellite Link
ISM
Industrial, Scientific, and Medical Applications or Information Systems Management (Intelsat)
ISMC
International Switching Maintenance Center
ISO
International Standards Organization or Isolation Diode
ISP
Specific Impulse
ISPC
International Sound Program Center
ISPO
Intelsat Spacecraft Project Office
ISPRS
International Society for Photogrammetry and Remote Sensing
ISR
Intelsat System Record
ISRO
Space Research Organization (India)
ISS
Information Sending Station or Inter Satellite Service or Interrupt Safety System or Ionosphere Sounding Satellite (Japan)
IST
Integrated System Test
ISTC
Integrated System Test Complex or International Switching and Testing Centers
ISTN
Integrated Switching and Transmission Network
ISU
Independent Signal Unit or Initial Signal(ing) Unit
ITA
Independent Television Authority (UK) or International Telegraph Alphabet
ITAF
Intelsat Technical Annex Facility
ITALSAT
Italian Communication Satellite System (Domestic Service - Italy)
ITC
International Television Center
ITCC
International Technical Control Center
ITDB
Integrated Traffic Data Base
ITE
International Telephone Exchange
ITM
International Transmission Maintenance or Integrated Telemetry Management
ITMC
International Transmission Maintenance Center
ITOS
Improved TIROS Operational Satellite (NDAA - USA)
ITPC
International Television Program Center
ITPR
Infrared Temperature Profile Radiometer
ITR
Intelsat Test Record
ITS
Insertion Test Signal
ITT
International Telephone and Telegraph Company (USA)
ITU
International Telecommunications Union
IUCAF
Inter-Union Commission on Allocation of Frequencies for Radio Astronomy and Space Science
IUE
International Ultraviolet Explorer
IUGG
International Union of Geodesy and Geophysics
IUPAP
International Union of Pure and Applied Physics
IUS
Inertial Upper Stage
IXC
Interexchange Carrier
JASC
Japan Sea Cable
JCL
Job Control Language
JF
Junction Frequency
JFET
Junction Field Effect Transistor
Jitter
The deviation in the time it takes for packets that are part of the same file to traverse the network, compared with the average delay time for all of the packets.
JIU
Joint Inspection Frequency
JPCD
Just Perceptible Color Difference
JPL
Jet Propulsion Laboratories (USA)
JRD
Joint Requirements Development
JSC
Johnson Space Center (USA)
JSD
Justification Service Digit
K or k
K Boltzmann's Constant or K Kelvin (degrees Kelvin) or K Kilohm (1,000 ohms) or k Kilo (103 )
K-band
Frequency Spectrum 10.9 to 36 GHzK-band
kA
Kiloampere
Ka-band
Loosely used for 30/20 GHz satellite systems or Used loosely for 30/20 GHz frequency spectrum
KAG
Kagoshima Space Center (Japan)
kb
Kilobit
kb/s OR kbit/s OR kbps
Kilobits Per Second
KERMA
Kinetic Energy Released in Material
keV
Kiloelectron volt
KFPA
K-band Full Performance Antenna
Kg
Kilogram
kH
Kilohenry
kHz
Kilohertz (1000 cycles per second)
kJ
Kilojoules
KLY
Klystron or klystron tube
km(s)
Kilometer(s)
KP
Start of Pulsing
KSC
Kennedy Space Center (USA)
Ku-band
Loosely used for 10.7 to 18 GHz satellite systems
kV
Kilovolt
kVA
Kilovoltampere
kW
Kilowatt
kWh
Kilowatt-hour
L
Inductance or inductor
L-band
Frequencies in the spectral region of 1.5 GHz or Loosely used for 1.6 GHz Maritime satellite systems
L-SAT
Experimental Satellite Network (ESA)
LAE
Liquid Apogee Engine
LAGEOS
Laser Geodynamic Satellite (USA)
LAM
Liquid Apogee Motor
LAMAR
Large Area Modular Array of Reflectors
LAMMR
Large Antenna Multifrequency MW Radiometer
LAN
Local Area Network
LANDSAT
Earth Resources Survey Satellite (USA)
LAP
Link Access Protocol/Procedure
LAPB
Link Access Protocol Balanced
LAS
Low-Altitude Observation Satellite
LASCR
Light-Activated Silicon-Controlled Rectifier
LASCS
Light-Activated Silicon-Controlled Switch
LASER OR laser
Light Amplification by Stimulated Emission of Radiation
LASSII
Low Altitude Satellite Studies of Ionosphere
LAST
Large Aperture Scanning Telescope
LAT
Latitude
LATA
Local Area Transport Arrangement
LB
Local Battery
LBS
Liquid Bipropellant Subsystem
LC
Inductance or Capacitance or Conductance or Loop Circuit
LCC
Launch Control Center (Intelsat)
LCD
Liquid Crystal Display
LCH
Latch
LCM
Load Current Monitor
LCMU
Load Current Monitor Unit
LDD
Linear Delay Distortion
LDM
Linear-Delta Modulation
LDOE
Longitude Drift/Orbit Eccentricity
LEAC
Laboratory Engineering Assistance Contract
LEASAT
U.S. Military Satellite Network (USA)
LEC
Local Exchange Carrier
LED
Light Emitting Diode
LEM
Logical End of Media
LEO
Low Earth Orbit
LETF
Launch Equipment Test Facilities
LF
Line Feed or Line Filter or Low Frequency
LFM
Link Framing Module
LHA
Local Hour Angle
LHCP
Left Hand Circular Polarization
LIDAR
Light Detection and Ranging
LIFO
Last In - First Out
LINCOMPEX
Linked Compressor and Expander
LIPS
Link Performance Simulation Program
LK
Lock
LLF
Line Link Frame
LLIP
Launch Loads Instrumentation Processor
LM or Lm
LM Limits Program or LM Lunar Module or Lm Lumen
LMA
Limited Motion Antenna
LMS
Level Measuring Set
LMSS
Land Mobile Satellite Service
LMT
Local Mean Time
LMTR
Limiter
LNA
Low-Noise Amplifier
LNB
Low-Noise Block-Down Converter
LNC
Low Noise Converter
LNR
Low Noise Receiver
LO
Local Oscillator
logamp
Logarithmic Amplifier
LON
Longitude
LOPs
Omega Lines of Position
LOR
Loran
LORAN-C
Long Range Navigational System
LOS
Line of Sight or Line Out of Service or Loss of Signal
LOUTCH
Ku-band Satellite Networks (Russian Federation)
LOX
Liquid Oxygen
LP
Line-up Preparations or Link Processor
LPA
Low Power Amplifier
LPC
Linear predictive coding
LPE
Liquid Phase Epitaxy
LPF
Low Pass Filter
LPS
Launch Process System
LRC
Langley Research Center (USA)
LRE
Low Rate Encoding
LRE/DSI
Low Rate Encoding with Digital Speech Interpolation
LRFAX
Low Resolution Facsimile
LRG
Launch Risk Guarantee
LRIR
Limb Radiance Inversion Radiometer
LRPM
Long Range Planning Model
LRR
Launch Readiness Review
LS
Letter Shift or Link Switch
LSB
Least Significant Bit
LSD
Least Significant Digit
LSE
Line Signaling Equipment
LSI
Large Scale Intigration
LSM
Line Switch Marker
LSO
Line Signaling Oscillator
LSP
Label Switch Path or Launch Support Process
LSR
Label Switch Router
LST
Large Space Telescope (NASA Satellite - USA) or Lease and Sales Transmission Program
LSU
Leading Signal Unit or Lone Signal Unit
LTC
Local Telephone Circuit or Long-Term Commitment
LTOM
Less Than One Minute
LTOS
Less Than One Second
LTT
Lower-tier test
LU
Line-Up or Logical Unit
LUF
Lowest Usable Frequency
LUXSAT
Satellite Network (Luxembourg)
LV
Latched Valve
M bit/s OR MB/s OR Mbps
Megabits per second
M or m
M Mega/Million or m Meter (e.g., 12m dish antenna) or m Micrometer or m Modulation Index (fm) or m Number of phases (PSK)

Square meter
mA OR MA
mA Milliampere or MA Multiple Access
MAC
Multiplexed Analogue Components or Mutual Aid Committee
MAD
Monitoring and Diagnostic Unit
MAG
Magnitude
MAGE
Mechanical Aerospace Ground Equipment
MAMSK
Multitone AMSK
MAP
Middle Atmosphere Component
MAPS
Measurement of Pollution from Satellite
MARECS
Maritime Experimental Comsat System (ESA) (formerly MAROTS)
MARISAT
Maritime Satellite System (USA)
MAS
Multi-Administration (satellite) System
maser OR MASER
Microwave Amplification by Stimulated Emission of Radiation
MAWG
Mutual Aid Working Group
MAXIT
Maximum Interference Threshold
MB
Metric Burst
MBA
Multiple Beam Antenna
MBB
Messerschmitt-Bolkow-Blohm (Germany)
MBC
Miniature beryllia circuit
MBPC
Multiple Burst Per Carrier
MBps
Megabits Per Second
MBPT
Multiple Burst Per Transponder (or Transmitter)
MBTA
Multiple Beam Torus Antenna
MBTP
Master Burst Time Plan
MC
Maintenance Center or Maneuver Coordinator or Master Clock
MCC
Master Control Console or Multi Channel Converter
MCE
Motor Control Electronics
MCH
Map Change Handler
MCLF
Multichannel Loading Factor
MCPC
Multiple Channels Per Carrier
MCS
Maritime Communications Subsystem or Multi-Channel Synchronizer
MCU
Monitor and Control Unit
MCVFT
Multichannel Voice Frequency Telegraphy
MCW
Memory Control Word or Modulated Continuous Wave
MD
Multi-Destinational or Multi-Dimensional
MDA
Mechanically Despun Antenna
MDE
Motor Drive Electronics
MDF
Main Distribution Frame
MDFD
Multi-Destination Full Duplex
MDHD
Multi-Destination Half Duplex
MDS
Minimum Discernible Signal
MDTA
Modulatdor-Demodulator Translator Assembly
MDUS
Medium Data Utilization Station (Australia)
ME
Managed Element
MECH
Mechanism
MECO
Main Engine Cutoff
Mega
Million
MELCO
Mitsubishi Electric Corporation (Japan)
MEM
Memory
MEOP
Maximum Expected Operating Pressure
MESH
Matra-ERNO-SAAB-Hawker Siddeley Dynamics Aerospace Consortium
MET
Mission Elapsed Time
Meteor
Meteorological Satellite (Russian Federation)
Metro Ethernet
A network in which the customer interface is Ethernet based, and is typically offered in a metropolitan area versus over a wide area
METSTAT
Meteorological Satellite
mf OR MF
MF Medium Frequencies (Band 6) or mf OR MF Multifrequency (refers to a type of trunk signaling system)
MFC
Compelled Multifrequency Signalling
MFR
Manufacturer or Multi-Frequency Register (refers to MF signalling system)
MFS
Magnetic field strength or Major Frame Synchronizer or Multifrequency Sender (refers to MF signalling system)
mg OR MG
mg Milligram or MG Motor Generator
MGC
Multigroup Controller
mH
Millihenry
MHD
Magnetohydro-dynamics
MHz
Megahertz (one million cycles per second)
MIC
Microwave Integrated Circuit
MIFR
Master International Frequency Register (record of frequency assignments maintained by the IFRB) (ITU)
MIL-STD
Military Standards
MINIT
Minimum Interference Threshold
MIOS
Modular Input-Output System
MIP
Master Index Pulse or Multigroup Interference Processor
MIPR
Master Index Pulse Reference
MIPRG
Master Index Pulse Reference Generator
MIS
Management Integrated System
MJD
Modified Julian Date
MKS
Meters, Kilograms, and Seconds
ML
Mean Life
MLA
Microwave link Analyzer
MLI
Multilayer Insulation
MLO
Master Local Oscillator
MLS
Microwave Landing System or Multi Line Switch
mm
Millimeter
MMH
Monomeghyl Hydrazine
mmHg
Millimeter of mercury
MMIC
Monolithic Microwave Integrated Circuit
MML
Man-Machine Language
MMS
Maritime Mobile Service or Matra Marconi Space or Multimission Modular Spacecraft
MMSS
Maritime Mobile Satellite Services
MMV
Multimission Modular Vehicle
MMW
Millimeter Wave
MNRU
Modulated Noise Reference Unit
MNVR
Maneuver
MOC
Management Observation and Conference Room
MOD
Microwave Oscillator Diode
Mod or MOD
Modulator
modem OR MODEM
Modulator or Demodulator
MOF
Maximum Observed Frequency
MOI
Minutes of Inertia or Moment of Inertia
MOL or mol
MOL Manned Orbital Laboratory or MOL Molniya Domestic Satellite (Russian Federation) or mol Mole (Amount of Substance)
MON
Monitoring Station or Monitor
mono
Monostable
MOPT
Mean One-way Propagation Time
MORE
Maritime system (Russian Federation)
Morelos
Domestic satellite system (formerly Ilhuicahua - Mexico)
MOS
Metal Oxide semiconductor or Metal Oxide Silicon
MOSFET
Metal Oxide Semiconductor Field Effect Transistor
MOST
Metal-Oxide Semiconductor TransistorM
MOU
Memorandum Of Understanding
MPA
Medium Power Amplifier
MPEG
Moving Picture Experts Group
MPLS
Multi-Protocol Label Switching
MPLS Label
A short, fixed-length identifier that is used to determine the forwarding parameters of a packet on an MPLS network
MPM
Multilateral Planning Meeting
MPOD
Monopod
MPRS
Master Primary Reference Station
MPRT
Master Primary Reference Terminal
MPSK
Multiple-Phase Shift-Keying
MPU
Microprocessing Unit
MRB
Materials Review Board
MRIR
Medium Resolution Infrared Radiometer
MRR
Manufacturing Readiness Review
MRS
Minimum Residual Shutdown
ms OR mS
ms Millisecond or mS Millisiemens
MSA
Metropolitan Statistical Area
MSAT
Canadian Mobile Satellite System
MSB
Most Significant Bit
MSC
Management Services Contract(or)
MSD
Most Significant Digit
MSED
Minimum Signal Element Duration
MSFN
Manned Space Flight Network
MSI
Medium-Scale Integration
MSK
Minimum Shift Keying
msl
Minimum Sea Level
MSM
Microwave Switch Matrix
MSR
Multifrequency Signal Register
MSS
Mobile Satellite Service or Multi-channel Synchronizing System or Multi-Spectral Scanner or Multichannel Synchronizing System or Multifrequency Signal Sender
MSSF
Mate Scanner Stop Failure
MST
Mixed Simulation Tests
MSU
Maintenance Signal Unit or Microwave Sounding Unit or Multiblock Synchronization Signal Unit or Multiple Signal Unit
MSW
Microwave Spectrometer
MTBF
Mean Time Before/Between Failures
MTC
Main Trunk Circuit (WMO)
MTF
Modulation Transfer Function
MTP
Master/Motor Burst Time Plan
MTR
Motor
MTS
Message Telecommunications/Telephony Service
MTTF
Mean Time To Failure
MTTR
Mean Time To Restore/Repair
MTU
Magnetic Tape Unit
MU
Multi-Destination Unidirectional
MUF
Maximum Usable Frequency
MUL
Multi-use
MULT
Multiple
Multicast
A network technology for transmission of data files from a single source to multiple destinations efficiently, without duplicate use of bandwidth on the network. Contrast with Unicast
MUM
Multi-Unit Message
MUSE
Monitor of Ultraviolet Solar Energy
Mux OR MUX
Multiplexer
mV
Millivolt
MVBR
Multivibrator
MW or mW
MW Microwatt or MW Microwave or mW Milliwatt
MWA
Momentum Wheel Assembly
Mykotronx
(MYKO) A type of Ground Encryption Unit
n or N
n Nano (one-Billionth) or N Negative or N Newton
n-QAM
N-state Quadrature Amplitude Modulation
n.mi
Nautical mile
N/A
Not Applicable
N/I
Noise to Interference Ratio
nA
Nanoampere
NAB
National Association of Broadcasters (USA)
NACD
Network Autonomous Commanding Display
NACK
Negative Acknowledgement
NAM
National Association of Manufacturers (USA)
NAND
Type of logic circuit
NAS
National Academy of Sciences (USA)
NASA
National Aeronautics and Space Administration (USA)
NASC
National Aeronautics and Space Council (USA)
NASCOM
NASA Communications Network (USA)
NASDA
National Space Development Agency (Japan)
NAT/TFG
North Atlantic Traffic Forecasting Group
NAVSAT
Satellite Navigation Corporation Navy Satellite (US)
nb OR NB
Narrow Band
NBC
National Broadcasting Corporation (USA)
NBFM
Narrowband Frequency Modulation
NBR
No Burst Received
NBTR
Narrowband Tape Recorder
NC
Network Congestion/Concentrators
NCAP
Nonlinear Circuit Analysis Program
NCC
Network Control Center
NCM
Network Controller Module (Timeplex card)
NDB
Nondirectional Radio Beacon
NDES
Normal Digital Echo Suppressor
NDT
Nondestructive Test
NEA
Noise Equivalent Angle
NEC
Nippon Electric Company (Japan)
NESC
National Environmental Satellite Center (USA)
NESS
National Environment Satellite Service
Network Latency
Network Latency in a packet-switched network is the time it takes packets to traverse the network from source to destination.
nF OR NF
nF Nanofarad or NF Noise Figure
NGO
Non-Governmental Organization
nH
Nanohenry
NHK
Nippon Hoso Kyokai (Japan Broadcasting Corporation)
Ni-Cd
Nickel Cadmium
Ni-H2
Nickel Hydrogen
NIC
Nearly Instantaneous Companding
NICATELSAT
Compañía Nicaragüense de Telecomunicaciones por Satélite (Nicaragua)
NILS
Non-Intelsat Launch Support
NIMBUS
Meteorological Satellite (USA)
NIS
No Input Signal
NIST
National Institute of Standards and Technology (USA)
NL
New Line
NLR
Noise Loading Ratio
nm
Nanometer
NMC
National Meteorological Center (USA) (WMO)
NMCC
Network Management and Control Center
NMI
No Modular Input
NMOS
N-channel Metal Oxide Silicon
NMS
Network Management Signal
NNI
Network Node Interface
NOAA
National Oceanic and Atmospheric Administration (USA)
NOC
Network Operations Center
NOR
Not OR function or Type of logic circuit
NORAD
North American Air Defense Command (USA)
NORDSAT
Broadcast television satellite system for Nordic countries (Norway)
NOS
No Output Signal
NOSFER
(New master system for the determination of reference equivalents)
Np OR NP
Np Neper or NP Non-Preemptible
NPC
North Pacific Cable
NPN
Negative-Positive-Negative
NPNP
Negative-Positive-Negative-Positive
NPR
Noise Power Ratio
NPRC
Network Packet Recirculator/Concentrator
NPV
Net Present Value
NRDE
Non-Reference Diagnostic Equipment
NRMS
Network Reference and Monitoring Station
NRZ
Non-Return to Zero
NRZ-I
Non-Return-to-Zero-Inverted
NRZ-L
Non-Return to Zero-Low
NRZ-M
Non-Return to Zero Mark
NRZ-S
Non-Return to Zero-Space
NRZL
Non-Return to Zero Level
ns
Nanosecond (one-billionth)
NSA
National Security Agency (USA) or National Standards Association (USA)
NSC
Network Switching Center
NSCS
Non-linear Satellite Channel Simulator
NSF
National Science Foundation (USA)
NSI
NASA Standard Initiator
NSL
Net Switching Loss
NSPC
National Sound Program Center
NSR
No Signal Received
NSSDC
National Space Science Data Center (USA)
NTC
National Television Center or Network Transmission Committee (VITEAC)
NTI
Noise Transmission Impairment
NTIA
National Telecommunications and Information Administration (USA)
NTP
Network Terminating Point or Normal Temperature and Pressure
NTS
Navigation Technology Satellite
NTSC
National Television System Comittee
NTSC System
System of color television based on the recommendation of the NTSC using 525 lines and 60 fields with a video bandwidth of 4.2 MHz (US, Canada, Japan)
NTT
Nippon Telegraph and Telephone Public Corporation (Japan)
NTU
Network Terminating Unit
NU
Number Unobtainable
NUT
Nutation
nV
Nanovolt
NVR
Nonvolatile Residues
nW
Nanowatt
O/P
Output
O&M
Operation and Maintenance
OAO
Orbiting Astronomical Observatory
OAS
Orbit Adjust Subsystem or Organization of American States
OAU
Organization of African Unity
OB
Outside Broadcast
OBA
Optical Barrel Assembly
OBE
Out-of-Band Emission
OBN
Out-of-Band Noise
OBWR
On-board Waveform Regenerator
OC-#
Optical Carrier
OCC
Operations Control Center (Intelsat) or Other Common Carrier
OCE
On-Call Engineer
OCO
Oven Controlled Oscillator
OCW
Oscillator Control Word
OCXO
Oven-Controlled Crystal Oscillator
OD
Oceanographic Data Station
ODAS
Ocean Data Acquisition Systems (UNESCO)
ODBC
Open Database Connectivity (usually a driver) use support Microsoft ACCESS link and use SQL based d to tables.
ODD
Operator Distance Dialling
ODL
Orbital Design Life
OECD
Organization for Economic Cooperation and Development (UN)
OEM
Original Equipment Manufacturer
OES
Outgoing Echo Suppressor
OFHC
Oxygen-Free High Conductivity Copper
OFT
Orbital Flight Test
OGO
Orbiting Geophysical Observatory
OGR
Outgoing Repeater
OIRT
International Radio and Television Organization
OJT
On-the-Job Training
OLV
Oxidizer valve
OM
Orbital Mechanics
OMA
Operations Management Application
OMJ
Orthomode Junction
OML
Orbital Maneuver Life or Orbital Mission life
OMP
Orbital Mechanics Processor
OMS
Orbital Maneuvering System
OMT
Orthomode Transducer
OMUX
Output Multiplexer
ONC
Ordinary National Certificate (UK)
ONERA
Office National d'Etudes et de Recherches Aérospatiales (National Bureau for Aerospace Studies and Research)(France)
OODBMS
Object Oriented Database Management System
OOS
Orbital Operations System
OP
Output Processor
opamp
Operational Amplifier
OPD
Operation Parameter Data
OPSK
Octal Phase Shift Kying
OPTT
Office des Postes et Telecommunications du Togo
OPTUS
Australian Telecommunications Carrier
OQPSK
Offset Quaternary Shift Keying
OR
Operations Research or Type of logic circuit
ORACLE
Viewdata or teletext system similar to CEEFAX (BBC)
ORB
Obeyed Reference Burst
ORBIS
Orbiting Radio Beacon Ionospheric Satellite
ORION
Proposed Separate Satellite System
ORTF
Office de Radiodiffusion et Télévision Françaises(French Radio and Television Station)
OSC
Oscillator
OSCAR
Amateur Radio Communications Satellite (USA and Australia)
OSEOS
Operational Synchronous Earth Observatory Satellite
OSI
Open System Interconnection
OSM
Miniaturized Rigid Coaxial Cable
OSO
Orbiting Solar Observatory (USA)
OSPK
Off Set Keyed Quadrature Phase Shift Keying
OSR
Optical Solar Reflector
OSV
Ocean Station Vessel (ICAO, WMO)
OTCI
Override TSO Corection Interval
OTE
Hellenic Telecommunications Organization, S.A.(Greece)
OTEC
Ocean Thermal Energy Conversion
OTI
Ibero-American Television Organization
OTLP
Zero Transmission Level Point
OTP
Office of Telecommunications Policy (USA)
OTS
Orbital Test Satellite
OTV
Orbital Transfer Vehicle
OU
Occasional Use
OUB
Occasional Use Bands
OVERVLTG
Over Voltage
OW
Order Wire
OWF
Optimum Working Frequency
OXD
Oxidizer
P OR p
P Microprocessor or P Peak or P positive or p OR P Pico (one trillionth) or p pico- (10-12) or p Private or Special Telephone Circuit (CCITT)
P-P OR p-p OR p.p. OR pp
Peak-to-Peak
p.e.p. OR PEP
Peak Envelope Power
p.f.d OR PFD
Power Flux Density
P2MP
Point to multipoint
P2P
Point to point
PA or pA
PA Power Amplifier or pA Picoampere or pA Preassigned or pA Public Address
PABX
Private Automatic Branch Exchange
PAC
Platform Azimuth Control
Packet
A formatted block of data that is routed between an origin and a destination on a network.
Packet Loss
A type of error on a digital network that occurs when one or more packets of data traveling across a network fail to reach their destination.
PAD
Packet Assembly and Disassembly
PADS
Development Laboratories
PAGEOS
Passive Geodetic Earth-Orbiting Satellite (NASA - USA)
PAL
Phase Alternation Line (TV standard)
PAL-M
PAL System using NTSC Parameters
PALAPA
Domestic satellite system (Indonesia)
PAM
Payload Assist Module or Pulse Amplitude Modulation
PAM-D
Payload Assist Module D
PAMA
Pulse Address Multiple Access
PAML
Program Authorized Materials List
PANA
Pan-African News Agency
PANAFTEL
Pan-African Telecommunication Network
PanAmSat
Alpha Lyracom Space Communications Satellite Network (USA)
PANDA
Pivot-Assisted Nutation Damping Assembly
PAPM
Pulse Amplitude and Phase Modulation
Par OR PAR
Par OR PAR Parity or PAR Peak to Average Ratio
Paramp
Parametric amplifier
PAT
Pending Alarms Control Table
PATU
Pan-African Telecommunications Union
PAX
Private Automatic Exchange
PBC
Program Booking Center
PBER
Pseudo Bit Error Rate (pseudo BER)
PBK
Playback Mode
PBM
Perigee Boost Motor
PBS
Public Broadcasting System (USA)
PBX
Private Branch Exchange
PC or pc
PC Personal Computer or pc OR PC Printed Circuit
PCA
Polar Cap Absorption
pcb OR PCB
Printed Circuit Board
PCE
Power Conditioning Electronics
PCI
Pattern Correspondence Index or Telecommunication Company of Iran
PCM
Payload Change Out Room or Pulse Code Modulator/Modulation
PCMID
Pulse Command ID
PCU
Power Control Unit or Print Control Utility
PDA
Predetermined Arc
PDC
Platform Despin Controller
pdf OR p.d.f.
Probability Density Function
PDH
Plesiochronous Digital Hierarchy
PDL
Program Design Language
PDM
(syn.: pulse width modulation) or Pulse Duration Modulation
PDN
Public Data Network
PDR
Preliminary Design Review
PDS
Planned Domestic Services
PDTS
PCM/DSI Test Set
PDUS
Primary Data Receiving Station (Meteosat)
PE
Pictorial Element or Project Engineer
PEC
(Marconi SCG)
PEM
Proto Environmental Model
PERT
Project Evaluation and Review Technique
PERUMTEL
Perusahaan Ummum Telekonunikasi (Indonesia)
PES
Post-Ejection Sequencer
PESC
Telephone Engineering Service Circuit
pF OR PF
pF Picofarad (Unit of electrical capacitance) or PF Power Factor
PFB
Provisional Frequency Board
PFIX
Power Failure Interrupt
PFM
Protoflight Model or Pulse Frequency Modulation
PFO
Pilot Frequency Oscillator
PG
Permanent Glow
PGM
Program
PGP
Pretty Good Privacy
PH
Packet Handler or Phase
Phebus
European Experimental Broadcast Television Satellite (also H-Sat)
PHILCOMSAT
Communications Satellite Corporation (Philippines)
Pico
A trillionth
PID
Parameter Identification Directory
PIL
Pilot
PIM
Passive Intermodulation or Pulse Interval Modulation
PIN
Parameter Identification Number / Name or Positive-Intrinsic-Negative
PIP
Payload Integration Plan
PIRC
Pacific and Indian Ocean Restoration Committee
PIU
Payload Interface Unit
PIV
Peak Inverse Voltage
PKM
Perigee Kick Motor
PKO
Project Kick-Off meeting
PL
Parts List or Path Loss or Platform or Project Library
PLD
Phase-Locked Demodulator
PLE
Plesetsk Launch Complex (Russian Federation)
PLL
Phase-Locked Loop
PLS
Phase-Lock system
PLU
Phase Lock Unit
PM
Permanent Magnet or Phase/Pulse Modulation
PMA
Permanent Management Arrangements
PMB
Proto Main Body
PMBX
Private Manual Branch Exchange
PMD
Propellant Management Device
PMF
Perigee Motor Firing
PMO
Project Management Office
PMOS
P-channel MOS
PMR
Pressure Modulated Radiometer
PMS
Picturephone Meeting Service
PMU
Propellant Management Unit
PN
Positive-Negative junction or Pseudo-Noise
PNM
Pulse Number Modulation
PNP
Positive-Negative-Positive junction
PNPN
Positive-Negative-Positive-Negative
PNS
Primary North-South Stationkeeping
POCA
Point of Closest Approach
POGO
Polar Orbiting Geophysical Observatory
POL
Polarization or Problem Oriented Language (computer)
Polang
Polarization Angle
PoP
Point of Presence
POR
Pacific Ocean Region
POS
Positioning
pot OR POT
Potentiometer
POTOK
Satellite Network (Russian Federation)
PP
Patch Panel
PPA
Platform Pointing Angle
PPF
Payload Processing Facility
PPI
Plan Position Indicator
ppm OR PPM
PPM Parts Per Million or PPM Peak Program Meter or PPM Periodic Permanent Magnet or PPM Platform Pointing Mode or PPM Pulse Position Modulation or ppm OR PPM Parts Per Million
PPS
Pulses Per Second
PPU
Power Processor Unit
PQM
Proto Qualification Model
PR
Preemptible or Pseudo-Random
PRB
Primary Reference Burst
PRBS
Primary Reference Burst Sequence or Pseudo-Random Bit Sequence Pseudo-Random Binary Sequence
Preamp
Preamplifier
PRESTEL
Tradename for the United Kingdom Post Office Corporation's viewdata or telex service (UK)
PRF
Pulse Repetition Frequency
PRFD
Pulse Recurrence Frequency Discrimination
PRI
Primary
PRN
Pseudo-Random Noise
PROC
Processor
Progress
Modified Automatic Soyuz Cargo Spacecraft (Russian Federation)
PROM
Programmable Read Only Memory - silicon chips that are "burnt" according to NSA's KI-23 algorithm. These chips, sometimes referred to as "PROMs" or "Keys", consist of 24 six (6) bit words. Each word is used to select a certain bit in the 63-bit shift register contained within an encryption/decryption device. These chips are loaded into a ground encryption unit (GEU) and onto a S/C decryption unit. When a GEU is instructed to select a location, and then passed a string of 63 bits, the "key" loaded in this location, will cause the 63 bits in this string to be uniquely shifted to different positions.
PROP
Propulsion
PRPM
Primary Power Monitor
PRR
Pulse Repetition Rate
PRT
Primary Reference Terminal
ps OR PS
ps Picosecond or PS Power Supply
PSC
Perigee Stage Cradle
PSD
Performance Start Date
PSDU
Perigee Stage Driver Unit
PSI OR psi
PSI Paid Service Indication or psi OR PSI Pounds Per Square Inch
psia
Pounds Per Square Inch Absolute
psid
Pounds Per Square Inch differential
psig OR PSIG
Pounds Per Square Inch Gauge
PSK
Phase Shift Keying
PSM
Power System Monitor
PSN
Primary North/South Stationkeeping or Public Service Newsgathering
PSSC
Public Service Satellite Consortium (USA)
PSTN
Public Switched Telephone Network
PSU
Power Supply Unit
PTAT
Private Transatlantic Cable
PTC
Pacific Telecommunications Council
PTD
Proceed-To-Dial (signal)
PTDS
Program Track Data Switch
PTLU
Pre-Transmission Line-Up
PTM
Pulse Time Modulation
PTS
PCM Telemetry Switch or Proceed-to-Select/Send (signal)
PTT
Post, Telegraph, Telephone (general designation) or Push-To-Talk
PULSAR
Pulsed Sequential Access Relay
PUT
Programmable Uni-junction Transistor
PV
Present Value
PVA
Perigee Velocity Augmentation
PVC
Polyvinyl Chloride
pW
Picowatt
PWM
Pulse Width Modulation
PWMP
Psophometrically Weighted Mean Power
pWp
Picowatt psophometrically weighted
pWp0
Picowatt Psophometrically weighted measured at a point of zero transmission level (0TLP)
PWR
Power
Q
Quality Factor or Queue
QA
Quality Assurance
QAM
Quad Asynchronous I/O Module or Quadrature Amplitude Modulation or Quadrature Asynchronous I/O Module or Quadrature Asynchronous Multiplexer (Timeplex)
QAM-PAM
Quadrature Amplitude Modulation-Pulse Amplitude Modulation
QASK
Quadrature Amplitude Shift Keying
QAT
Quick Roll Estimate Attitude Trim
QC
Quality Control
QDU
Quantization Distortion Unit
QM
Qualification Model
QoS
Quality of Service (QoS) � Quality of service is the ability of a network to provide different priority to different applications, users, or data flows, or to guarantee a certain level of performance to a data flow.
QPRS
Quadrature Partial-Response System
QPSK
Quaternary Phase Shift Keying
QPSK/FDMA
Quaternary Phase Shift Keying/ Frequency Division Multiple Access
QRP
Low-power amateur radio
QSM
Quad Synchronous Module
QSS
Quasar (Quasi-Stellar Radio Source)
QTY
Quantity
QVM
Quadrature
R
Degree Rankine or Resistance or Resistor or The Gas Constant or The Ryberg Constant or Transmission Rate
R&D
Research and Development
R&QA
Reliability and Quality Assurance
RA NODE
Right Ascension of Ascending Node
Ra or RA
Ra Radium (chemical symbol) or RA Right Ascension
RAC
Repeat Automated Command
Rad OR RAD
Radian
RADA
Random Access Discrete Address
RADAR
Radio Receiving and Ranging
RADTR
Radiator
RAF
Rate Adjustment Factor
RAG
Request Handling and Assignment Generation
RAM
Random Access Memory
RAMS
Random Access Measuring System
RARC
Regional Administrative Radio Conference
RAS
Remote Analysis System
RASCOM
Regional African Satellite Communications System
RB
Reference Burst
RBD
Reference Burst Distribution
RBID
Reference Burst Identification
RBOC
Regional Bell Operating Company (USA)
RBU
Receive Baseband Unit
RBV
Remote Beam Vidicom
RBW
Reverse Band Working
RC
Remote Control or Resistance/Capacitance (-or/-or) or Resistance-Capacitor
RCA
Radio Corporation of America (USA)
RCC
Rescue Coordination Center
RCEC
Repayment of Capital/Excess Compensation Account
RCO
Restoration Control Office
RCP
Receive Channel Processing Function or Remote Command Processor or Restoration Control Point
RCS
Reaction Control (Sub)System
RCT
Reaction Control Thruster or Reference Command Table
RCTL
Resistor-Capacitor-Transistor Logic
RCTP
Retransmitted Condensed Burst Time Plan
RCV
Reveive or Receiver
RDARA
Regional and Domestic Air Route Area
RDB
Rate Distortion Bound
RDF
Repeater Distribution Frame
RDG
Receive Data Gate
RDM
Read-only Memory
RDSS
Radio Determination Satellite Service
RDU
Remote Decoder/Distribution Unit
RDUR
RCS Duration
RE
Earth Radii or Reference Equivalent
REA
Reaction Engine Assembly
RECON
Battery Reconditioning
RED
Redundant
REJ
Receiving Reject
REL
Relative or Release
RELP
Residual Excited Linear Processor
RELRATE
Relative Rate
REOR
Reorientation
REP
Repetition
RESTEC
Remote Sensing Technology Center (Japan)
RET
Reliable Earth Terminal
RF
Radio Frequency
RFC
Request For Change
RFI
Radio Frequency Interference or Request For Information
RFP
Request For Proposal
RFQ
Request For Quotation
RFS
Ready For Service or Receive Frame Synchronization or Request For Switchover
RG
Guard Release
RGB
Red-Green-Blue
RGM
Release Guard Message
RHCP
Right Hand Circular Polarization
RI
Repeat Indication
RIF
Receive IF
RIM
Receiver Intermodulation
RIP
Ring Interface Processor
RIS
Retransmission Identity/Indication Signal
RJE
Remote Job Entry
RL
Return Loss
RLO
Restoration Liaison Officer
RLSF
Release Failure
RLY
Relay
RMA
Random Multiple Access
RMAC
Remote Monitoring and Control
RMBAFN
Reconfigurable Multibeam Antenna Feed Network
RMC
Regional Meteorological Center (WMO)
RMI
Route Monitoring Information
RMS OR rms
RMS Remote Manipulator System or RMS Resource Management System or rms OR RMS Root Mean Square
RMTE
Remote
RN
Radio Networking System or Reference Noise
RNG
Ranging
RNI
Ready for Network Integration
RO
Receive Only
ROI
Return on Investment
ROM
Read Only Memory or Rough Order of Magnitude
ROP
Reference Terminal Operational Parameters
ROSAT
Roentgen Satellite (Germany)
ROTV
Receive-Only television
RPLY
Reply
rpm OR RPM
Revolutions Per Minute
RPOA
Recognized Private Operating Agency
RPOE
Recognized Private Operating Entity
RPS OR rps
RPS Relative Performance Score or rps OR RPS Revolutions Per Second
RPU
Ranging Processing Unit
RQ
Repetition of Information
RR
Radio Regulations
RR/u
Revenue Requirements per Unit
RRE
Receiving Reference Equivalent
RRL
Radio Research Laboratories (Japan)
RRM
Relative Rate Mode
RRS
Retransmission Request Signal
RRT
Relative Rate Fault Detection and Recovery or Relative Rate Toggle
RS
Reed Solomon (block) encoder/decoder Record Separator or Roving Spot
RSA
Revenue and Signatory Accounting
RSAN
Remote Spectrum Analyzer Network
RSD
Radial Spin Down
RSE
Register Signaling Equipment or Rotor State Estimator
RSO
Redundancy Switchover
RSP
Receive Shift Pulse
RSR
Revenue System Redevelopment
rss OR RSS
Root Sum Squares
RSSD
Reference Station Status Display
RST
Reference State Table
RSTN
Regional Seismic Test Network
RSU
Radial Spin Up or Redundancy Switching Unit
RT
Radiotelephone
RTCTP
Reference Terminal Condensed Burst Time Plan
RTE
Real Time Executive or Reference Terminal Equipment
RTE-A
HP 1000 Operating System
RTE/TSM
TDMA Reference and Monitor Station Equipment
RTEP
Reference Terminal Equipment Processor
RTF
Radiotelephony
RTG
Radio-isotope Thermoelectric Generator or Radiotelegraphy or Receive Timing Generator
RTH
Regional Telecommunication Hub
RTI
Real Time Interrupt
RTL
Resistor-Transistor Logic
RTM
Redundant Telemetry Modules
RTNR
Ring Tone No Reply
RTP
Real Time Peripheral or Reference Terminal Time Plan
RTT
Ratioteletype or Régie des Télégraphes et des Téléphones (Belgium)
RTU
Remote Telemetry Unit
RUD
Receive Channel Status Update and Overload Canal Decoding Process
RURAX
Rural Automatic Exchange
RX OR Rx
Receive/Receiver
Rz OR RZ
Return to Zero
S or s
S Distance along a path (phys., chem.) Specific Entropy or s Microsecond or S Pointing vector or s Second (time) or S Shortwave or S Siemens (phys.) or S Sulphur
S-meter
Signal-Strength meter
S/C
Spacecraft
S/C Key
The term used to indicate a unique location within a decryption unit on-board a S/C
S/EOS
Standard Earth Observation Satellite
S/I
Signal-to-Interference Ratio
S/N
Signal-to-Noise Ratio
S/Q
Signal Quality Value
S+DX
Speech+Duplex (Simultaneous Speech and Telegraphy in a Voice Channel)
SABM
Set Asynchronous Balanced Mode command
SAC
Spin Axis Control
SAD
Space Antennae Diversity
SADA
Solar Array Drive Assembly
SADE
Solar Array Drive Electronics
SAGR
Supergroup Automatic Gain Regulator
SAIL
Shuttle Avionics Integration Laboratory (NASA - USA)
SAM
Selective Assignment Message or Stratospheric Aerosol Measurement (NASA Satellite - USA) or Subsequent Address Message or Surface-to-Air Missile
SAMOS
Air Force Reconnaissance Satellite (USA)
SAMS
Stratospheric and Mesospheric Sounder
SAMSARS
Satellite-Based Maritime Search and Rescue System
SAR
Search and Rescue or Successive-Approximation Register or Synthetic Aperture Radar
SARIT
Satellite Network (Italy)
SARSAT
Search and Rescue Satellite (US, Russian Federation, France and Canada)
SAS
Small Astronomical Satellite
SATCOM
Domestic satellite network (Owned by RCA American Communications, Inc. - USA)
SAW
Surface Acoustic Wave
SAX
Small Automatic Exchange
SB
Simultaneous Broadcast
SBPC
Single Burst per Transmitter/Transponder
SBTP
Secondary Burst Time Plan or Secondary/Simulator Burst Time Plan
SC
Service Channel or Satellite Channel or Service/Satellite Channel or Space Craft or Suppressed Carrier
SCA
Small Communications Antenna
SCATHA
Spacecraft Charging at High Altitudes Scientific Satellite (USA)
SCC
Satellite Control Center (Intelsat) or Sequential Control Code or Specialized Common Carrier
SCD
Service Commencement Date or Simultaneous Command Decoder
SCE
Spacecraft Control Electronics
SCF
Satellite/Spacecraft Control Facility
SCFM
Sub-carrier Frequency Modulation
SCG
Signal/Synchronous Command Generator
SCH
Seizures per Circuit per Hour
SCIM
Speech Communications Index Meter
SCMID
Serial Command ID
SCN
Software Change Notice
SCNA
Sudden Cosmic Noise Absorption
Scope
Oscilloscope
SCOR
Scientific Committee On Ocean Research
SCP
Satellite Channel Processing Procedure or Stored Command Processing
SCPC
PCM/PSK Telecommunications Equipment or Set Clock Phase Correction or Single Channel Per Carrier
SCPC/CFM
Single Channel Per Carrier/Companded Frequency Modulation
SCPDM
Suppressed Clock Pulse Duration Modulation
SCR
Selective Chopper Radiometer or Silicon Controlled Rectifier or Signal-to-Crosstalk ratio
SCS
Silicon-Controlled Switch
SCTO
Stalled Call Timed Out
SCU
System Control Signal Unit
SCUC
Satellite Communications Users Conference
SD
Single Destinational or Speech Detector
SD-SDI
Serial Digital Interface
SDCV
Spatially-dedicated Continuously-visible
SDF
Supergroup Distribution Frame
SDH
Synchronous Digital Hierarchy
SDI
Strategic Defense Initiative (USA)
SDL
Specification and Description Language
SDMA
Space Domain/Division Multiple Access
SDNTX
Selective Do Not Transmit
SDP
Solar Drum Positioner
SDRO
Selected Data Retrieval Output
SDS
Satellite Diagnostic Subsystem or Software Development System
SDU
Spun Driver Unit
SEA
Sudden Enhancement of Atmospherics
SEC
American Security Carrier or Secondary Emission Control
SECAM
Sequencial Couleurs à Mémoire - A color television system developed in France using 625 lines and 50 fields with a bandwidth of 6 MHz or Secondary (Sustainer) Engine Cutoff
SED
Service End Date or Spectral Energy Density
SEER
Secondary Electron Emission Ratio
SEG
System Engineering Group
SEL
Selected or Space Environment Laboratory (USA)
SELCAL
Selective Call/Calling
SEM
Scanning Electron Microscope or Space Environment Monitor
SEMS
Space Environment Monitor Subsystems
SEN
SENSE command or Sensor
SEOS
Synchronous Earth Observation Satellite
SEQ
Sequence
Service Availability
The percentage of time within the total time for a service ordered by a customer during which the service is available to successfully transfer customer content
SES
Severely Errored Seconds or Ship Earth Station or Ship/Standard Earth Station
SET
European Telecommunications Working Group of the CEPT
SETAB
(Working standard with subscriber's equipment)
SETED
(Working standard with an electrodynamic microphone and receiver
SEU
Single Event Upset
SFD
Saturation Flux Density
SFERT
Master Telephone Transmission Reference System
SFOF
Space Flight Operation Facility
SG
Super Group (CCIR/CCITT)
SGCS
Satellite Ground Control System (Intelsat)
SGDF
Supergroup Distribution Frame
SGP
Simplfied General Perturbation
SHA
Sidereal Hour Angle
SHAR
Sriharikota Island Launch Complex (India)
SHE
Spacecraft Handling Equipment
SHF
Super High Frequency 3,000 - 30,000 MHz Shuttle Launcher (NASA - USA)
SI
Speech Interpolation or Systeme Internationale (the international system of units of measurement)
SICC
Spanish International Communications Corporation (USA)
SICL
HP's Standard Instrument Control Library
SID
Sudden Ionospheric Disturbance
SIDEREAL
Sidereal clock time relative to orbit node
SIDM
Single Integration Delta Modulation
SIG
Senior Interagency Group or Signal
SIM
Simulator
SIMP
Satellite Interface Message Processor
SIR
Selected for Internal Reference or Selected Inertial Reference
SIRIO
Experimental Satellite Network (Italy)
SIT
Static Induction Transistor
SITC
Satellite International Television Center
SITE
Satellite Instructional TV Experiment
SIU
Signaling Interface Unit
SIV
Solar and Interplanetary Variability
SLA
Service Level Agreement
SLL
Satellite Line Link
SLMS
Selective Level Measurement Set
SLOHA
Slotted ALOHA
SLS
Side Lobe Suppression
SLT
Satellite Local Time
SMA
Search Mode Acquisition or Semi Major Axis
SMDU
Stepper Motor Drive Unit
SME
Solar Mesosphere Explorer (NASA Satellite - USA)
SMM
Solar Maximum Mission (NASA Satellite - USA)
SMS
Shuttle Mission Simulator or Synchronous Meteorological Satellite (USA)
SMY
Solar Maximum Year
SNDTX
Selective Do Not Transmit code
SNF
System Noise Figure
SNG
Satellite Newsgathering
SNIAS
Société Nationale Aérospatiale (France)
SNL
SYNCH Loss or Synchronization Loss
SNR
Signal-to-Noise Ratio
SNT
System Noise Temperature
SO
Shift-Out
SOC
Satellite Operations Complex
SOD
Satellite Operations Department
SOE
Sequence of Events
SOF
Satisfactory Operation Factor or Start of Frame
SOH
Start of Heading
SOI
Silicon-On-Isolator
SOLAS
Safety Of Life At Sea
SOM
Space Oblique Mercator or Start of Message
SONATEL
Société Nationale des Télécommunications (Sénégal)
SOP
Single Ocean Payload
SORF
Start of Receive Frame
SORMF
Start of Receive Multiframe
SOS
Silicon-On-Sapphire or Start of Service
SOTF
Start Of Transmit Frame
SOTMF
Start Of Transmit Multiframe
SOW
Statement of Work
Soyuz
Two-Man Spacecraft (Russian Federation)
SPACENET
Domestic satellite network (Owned by GTE - USA)
SPADE
SCPC PCM multiple Access Demand assigned Equipment
SPAS
Shuttle Payload Satellite
SPC
Stored Program Control
SPD
Synchronous Phase UW Detection
SPDT
Single Pole Double Throw
SPE
Signal Processing Equipment
SPEC
South Pacific Economic Cooperative or Speech Predicting Encoding Compression (System) or Speech Predictive Encoded Communications
SPELDA
Dual-launch system for heavy geostationary payloads, used by Ariane
SPF
Single Point Failure or System Performance Factor
SPI
Software Productivity Improvement or Special Position Identification (Pulse) or Station Program Identification
SPINE
Space Information Network Experiment (ESA)
SPL
Signal Processing Modem or Solar Proton Monitor or Sound Pressure Level
SPM
Signal Processing Modem
SPN
Spin
SPOT
Earth Observation Satellite System (France)
SPR
Software Problem Report
SPS
Solar Powered Satellite or System Performance Score
SPST
Single Pole/Single Throw
SPT
System Performance Test
Sputnik
Experimental satellite for manned space flights (Russian Federation)
SQL
Structured Query Language
SQRX
Square Axis Positioner
SR
Scanning Radiometer or Shift Register or Stripchart Recorder
SRA
Slip Ring Assembly
SRAEN
Reference system for the determination of articulation reference equivalents
SRARQ
Selective Repeat-Automatic Repeat Request
SRATS
Solar Radiation and Thermospheric Structure Satellite (Japan)
SRB
Secondary Reference Burst or Solid Rocket Booster
SRC
Source
SRD
Step Recovery Diode
SRE
Sending Reference Equivalent or Speech Recognition Equipment (or VRE) or Surveillance Radar (syn.: Search Radar)
SRF
Service Request Flag or Surface Roughness Equivalent
SRIP
Supplemental Retirement Income Plan
SRL
Stability Return Loss
SRM
Solid Rocket Motor
SRO
Synthesizer Reference Oscillator
SRP
Signal Reference Point
SRR
Shipment Readiness Review
SRS
Secondary Reference Station or Synchronous Relay Satellite
SRT
Secondary Reference Terminal or System Reliability Test
SRTS
Supporting RTE and TSM System
SS
Satellite Switching or Spread Spectrum or Start of Superframe
SS-TDMA OR SS/TDMA
Satellite-Switched Time Division Multiple Access
SS/L
Space Systems/Loral
SSB
Single Sideband (AM)
SSB-SC-AM
Single Sideband Suppressed Carrier Amplitude
SSB-SC-ASK
Single Sideband Suppressed Carrier Amplitude Shift Keyed
SSB-SC-PAM
Single Sideband Suppressed Carrier Pulse Amplitude Modulation
SSBTP
Satellite Switching Burst Time Plan
SSC
Satellite Situation Center or Satellite Switching Center (Intelsat) or Shift Supervisor's Console or Special Substitution Control
SSCTP
Satellite Switching Condensed Time Plan
SSD
Service Start Date
SSE
Space Segment Engineering
SSES
Space Segment Payload Engineers
SSFC
Sequential Single Frequency Code
SSI
Small-Scale Integration
SSLO
Solid State Local Oscillator
SSM
Satellite System Monitor or Signal Switching Matrix or Static Switch Matrix or Super Spin Mode or Support Subsystem Module
SSMA
Spread Spectrum Multiple Access
SSME
Space Shuttle Main Engine
SSMG
Satellite System Monitoring Group
SSMTP
Satellite Switching Master Time Plan
SSO
Simultaneous Sun Outage or Spontaneous Switch Off or Spontaneous/Spurious Switch-Off
SSOG
Satellite Systems Operations Guide (Intelsat)
SSOP
Satellite System Operations Plan
SSP
Sensor Suite Positioner Sub-Satellite Point or Signaling and Switching Processor
SSPA
Solid State Power Amplifier
SSPS
Satellite Solar Power Station
SSR
Steady State Reception
SSRA
Spread Spectrum Random Access
SSRTE
Satellite Switching Reference Terminal Equipment
SSSF
Self-Scanner Stop Failure
SST
Satellite-to-Satellite Tracking or Supersonic Transport
SSTDMA
Satellite Switched Time Division Multiple Access
SSTM
Station to Station Traffic Matrix
SSTP
Switch State Time Plan
SSTV
Slow Scan Television
SSU
Secondary Sampling Unit or Sequential Shunt Unit or Single/Subsequent Signal Unit or Stratospheric Sounding Unit
SSUS
Solid Spinning Upper Stage or Spin-Stabilized Upper Stage
SSV
Switch State Verification
ST
"End Pulsing" Command (CCITT format) or Standard Time or Successful Termination
STA
Structural Test Article
STAR
Satellite Telecommunications with Automatic Routing (Simple form of SPADE system)
STAT
Status
STATSIONAR
Communications Satellite for Geostationary Orbit Operation (Russian Federation)
STBY
Standby
STC
Switching and Testing Center or Synchronous Thruster Control
STCC
Spacecraft Technical Control Center
STD
Subscriber Trunk Dialing
STDN
Space Tracking and Data Network
STE
Spacecraft Test Equipment or Supergroup Translating Equipment
STELLA
Satellite Transmission Experiment Linking Laboratories (ESA)
STEP
Stepper
STETS
Solar Terrestrial Energy Transfer Studies
STIMAD
Société des Télécommunications Internationales de la République Malgache (Madagascar)
STIPS
Study of Traveling Interplanetary Phenomenon
STM
Structural Test/Thermal Model
STOM
Spade Terminal Operator's Manual
STOW
Stowed
STOX
Speech plus Duplex (speech and telegraphy in voice channel)
STP
Signal Transfer Point or Space Technology/Test Program (USAF)
STR
Strength or Symbol Timing Recovery
STRATS
Solar Radiation and Thermospheric Satellite (Japan)
Streaming
A method for delivering video or other content over a telecommunications network in a continuous flow
STRIP
Satellite Transmission Impairment Program
STRT
Start
STS
Space Transportation System (operated by NASA - USA)(the Shuttle)
STSK
Scandinavian Committee for Satellite Telecommunications
STX
Start of Text
SU
Signal Unit
SUB
Substitute Character
SUPARCOT
Space and Upper Atmosphere Research Commission (Pakistan)
SURVSATCOM
Survivable Communications Satellite
SVC
Secure Voice Communications Service / System
SVM
Space Vehicle Motor
SW
Short-Wave (radio) or Standing Wave or Switch
SWE
Spherical Wave Expansion
SWF
Short Wave Fadeout
SWG
Standard Wire Gauge
SWI
Special World Interval
SWIFT
Society for Worldwide Interbank Financial Telecommunications
SWL
Short-Wave Listener
SWOF
Switchover Operation Failure
SWR
Standing Wave Ratio
SYMCOSAT
Consortium for Symphony Satellite
Symphonie
Experimental Satellite System (France/Germany)
SYN
Synthesizer
SYNCH
Syncronize/Synchronizer
SYNCOM
Early Geostationary Satellite (USA)
SYNCOM IV
Experimental Satellite Designed by Hughes Aircraft for STS Launch (prototype for operational satellites for 1980's - USA)
SYSGEN
System Generation
SYU
Synchronous Signal Unit
t OR T
t Metric ton or T Tera (1012) or T Tesla (phys.) unit of magnetic flux density
T.I.M.
Télécommunications Internationales du Mali (Mali)
T.I.T.
Société des Télécommunications Internationales du Tchad (Chad)
T/R OR TR
Transmit/Receive
T/V
Thermal Vacuum
T&C
Telemetry and Command
T&EC
Tests and Evaluation Center
TA
Terminal Acquisition or Transistor Amplifier
TAAPM
Two-Axis Antenna Positioning Mechanism
TACSAT
Tactical Satellite (USA)
TAM
Total Assignment Message
TANC
Thrust Actuated Nutation Damping Control or Thruster Active Nutation Control
TARS
Turn Around Ranging Station
TAS
Terminal Acquisition Support
TASI
Time Assignment Speech Interpolation
TASO
Television Advisory Standards Organization or Television Allocations Study Organization
TASS
Terminal Acquisition and Synchronization Support
TAT
Transatlantic Telephone (USA/Europe) Cable
TAW
Terminal Acquisition Window
TB
Traffic Burst or Trunk Buffer
TBBF
Top Baseband Frequency
TBD
To be determined/defined/developed/done
TBM
Traffic Burst Monitor
TBMP
Traffic Burst Monitor Procedure
TBn
Traffic Burst No. n
TBTP
TSM Burst Time Plan
TBU
Transmit Baseband Unit
TC
Temperature Coefficient or Terrestrial Channel (satcom) or Transit Center or Trunk Circuit
TC&R
Telemetry, Command, and Ranging
TCA
Thrust Chamber Assembly or Time of Closest Approach
TCAR
TDMA Channel Assignment Record
TCC
Telephone Coordinating Circuit or Transmission Control Character
TCE
Telemetry and Command Equipment
TCEU
Telemetry and Command Extension Unit
TCH
Transparent Circuit Handler
TCI
TSO Correction Interval
TCM
Trajectory Correction Maneuvers or Trellis Coded Modulation
TCP
Thruster Control Processor
TCRG
Trunk Circuit Relay Group
TCS
Technical Communications Support or Thermal Control Subsystem
TCTP
Test Abridged CTP
TCTS
Trans-Canada Telephone System (Canada)
TCU
Thruster Control Unit
TCW
Telemetry Control Word
TCXO
Temperature-Compensated/Controlled Crystal Oscillator
TD-PSK
Time-Differential Phase-Shift Keyed System
TDA
Terminal/Tunnel Diode Amplifier
TDB
Traffic Data Base
TDC
Telegraphy Data Channel
TDF
Broadcasting Satellite Network (France)
TDG
Transmit Data Gate
TDHS
Test Data Handling System
TDL
Tapped Delay Line
TDM
Time Division Multiplex
TDMA
Time Division Multiple Access
TDMA/DNI
Time Division Multiple Access without Digital Speech Interpolation
TDMA/DSI
Time Division Multiple Access with Digital Speech Interpolation
TDMS
Telegraph Distortion Measuring Set or Time Shared Data Management System
TDP
Telemetry and Display Processors
TDR
Time Domain Reflectometer
TDRS
Tracking and Data Relay Satellite
TDRSS
Tracking and Data Relay Satellite System
TDS
Tracking and Data Acquisition Station or Triple Data Storage
TDU
TDMA Diagnostic Unit
TE
Threshold Extension or Transverse Electric mode
TEAGEN
Telemetry Event and Alarm Generation Module
TEC
Total Electron Content
TECD
TDMA Equipment Configuration Data
TED
Telemetry Event Detection or Threshold Extension Demodulator
TEL
Telephone
TELCOR
Instituto Nicaraguense de Telecomunicaciones y Correos (Nicaragua)
TELE-X
Experimental Satellite Network (Sweden)
TELECOM
Empresa Nacional de Telecomunicaciones de Colombia' or Satellite Network (France)
TELEDIREKTORATE
Telecommunications Administration (Norway)
TELESAT
Domestic Satellite (Canada)
TELESPAZIO
Societa per azioni per le comunicazioni spaziali (Italy)
TELEX
Switched Automatic Telegraph Subscriber Network
TEM
Transverse electric and magnetic mode
TEMP
Temperature
TERA OR TERRA
One trillion
TERLS
Thumba Equatorial Rocket Launching Center (India)
TERM
Termination
TESC
TDMA Engineering Service Circuits
TETTO
Toroidal Beam Telemetry Antenna
TEXTEL
Trinidad and Tobago External Telecommunications Co., Ltd.
TFA
Transmit Frame Acquisition
TFAS
Terminal Frame Acquisition and Synchronization
TFC
Traffic or Transmit Frame Counter
TFD
Telemetry Field Descriptor
TFE
Thuster Firing Electronics
TFG
Transmit Frame Generation
TFG-DM
Telemetry Format Generator - Dwell Mode
TFG-NM
Telemetry Format Generator - Normal Mode
TFM
Tamed frequency modulation
TFR
Theoretical Final Route
TFS
Transmit Frame Synchronization
TFT
Thin Film Transistor
TFU
Timing and Frequency Unit
TG OR Tg
TG Task Group (CCIR) or Tg OR TG Telegraph(y)
TGF
Through Group Filter
TH
Transponder/Time Hopping
THD
Total Harmonic Distortion
THR
Thruster
TID
Travelling Ionospheric Disturbance
TIE
Trunk Interface Equipment
TIFF
Tagged Image File Format (computer graphics)
TIG
Société des Télécommunications Internationales Gabonaises (Gabon) or Telegram Identification Group
TIM
TDMA/Terrestrial Interface Module or Time Interface Management or Transmitter Intermodulation
TIP
Tracking Impact Prediction (DUS Satellite)
TIROS
Meteorological Satellite (USA) or Television Infrared Observation Satellite
TIRS
Thermal Infrared Scanner
TIU
Terrestrial Interface Unit
TIUPIL
Typical Information Use Per Individual
TLM
Telemetry
TLP
Transmission Level Point
TM
Telemetered or Telemetry
TM/TC
Telemetry/telecommand
TMATV
Time multiplex analog television
TMF
Test and maintenance facility
TMN
Network or Telecommunications Management
TNIP
Terrestrial Network Interface Processor
TNS
TDMA network simulator
TOA
Time Of Arrival
TOC
Table of Coincidences or Table of Contents or Television Operating Center
TOCC
Technical and Operational Control Center (UK)
TOD
Time of Date or Time of Day
TOIRS
Transfer Orbit Infrared Earth Sensor
TOJ
Telecommunications of Jamaica Ltd.
TOPS
Telemetry Operations
TOR
Telegraph on Radio or Time of Receipt
TORQ
Torque
TOS
Time Ordered System or TIROS Operational Satellite (NASA - USA) or Transfer Orbit Stage
TOSSA
Transfer Orbit Sun Sensor Assembly
TOT
Time of Transmission
TOVS
TIROS Operational Vertical Sounder
TP
Telemetry Processor or Test Point
TPC
Transpacific Cable
TPD
Time Pulse Delay
TPL
Transmission Point Level
TPOD
Tripod
TPP
Telecommunication Preparatory Program
TPS
Therman Protection System
TPT
Transmission Path Translator
TRAD
Directional Telemetry Antenna
TRF
Tuned Radio Frequency
triac
Triode AC semiconductor switch
TRM
Transmit-Receive Module
TRMA
Time Randon Multiple Access
TRMS
TDMA reference and monitoring station
TRR
Test readiness review
TRT
Timing and Reference Transponder or Traffic Route Testing
TRU
Transponder Right of Use
TS
Telegraph Service (CCITT) or Terminal Synchronization or Test sequence or Time Source
TSC
Technical Services Contractor or Telegraph Service Circuit (CCITT)
TSCM
Terminal Service Channel Monitor
TSDE
Time Source Digital Electronics
TSDS
Terminal Stripchart Display System
TSESC
Telegraph Engineering Service Circuit
TSF
Through Supergroup Filter
TSGF
Through Supergroup Filter
TSM
TDMA System Monitor or Telephony Signaling Module
TSO
Time sharing option or Time Source Oscillator
TSP
Transmit Shift Pulse
TSPS
Traffic Service Positions System
TSS
Terminal Synchronization Support or Tethered Satellite System
TSSD
TDMA system status display
TSU
Tandem/Test/Telephone/Terminating Signal Unit
TT&C
Tracking Telemetry and Command
TT&R
Tracking, Telemetry and Ranging
TTB
Trunk Test Buffer
TTC OR TT&C
Tracking, Telemetry and Command
TTC&M
Tracking, Telemetry, Command and Monitoring
TTC&R
Tracking, Telemetry, Command and Ranging
TTF
Test Time Frame
TTG
Transmit Timing Generator
TTK
Time-To-Knee test
TTL, T 2L
Transistor-Transistor Logic
TTP
Trunk Test Panel
TTPB
Trunk Test Panel Buffer
TTS
TDMA/Traffic Terminal Simulator or Traffic Terminal Simulator
TTY
Telegraphic teletype/teleprinter/teletypewriter (order wire)
TU
Transmission Unit or Type of Unit
TURS
Timing unit redundancy selector
TUU
Transponder for Unrestricted Use
TV
Television (video and assigned audio)
TV-SAT
Satellite Network (Germany)
TV/FM
Frequency modulation television with associated audio FM-subcarrier
TVC
Thrust Vector Control
TVEC
Total Vertical Electron Content
TVI
Television Interference
TVRO
Television receive only Terminal
TVSC
Television Service Center
TVT
Television Typewriter
TW
Travelling wave
TWEB
Transcribed Weather Broadcast
TWERLE
Tropical Wind, Energy Conversion, Reference Level Experiment
TWT
Travelling Wave Tube
TWTA
Travelling Wave Tube Amplifier
TWX
Teletypewriter Exchange Service
TX
Transmitter or Transmit
TX/RCU
Transmit/Receive Control Unit
U/C
Up-Converter
U/D
Up/down chain
UA
Unnumbered Acknowledge Response
UAMPT
African and Malagasy Postal and Telecommunications Union
UAPT
African Postal and Telecommunications Union
UARS
Upper Atmospheric Research Satellite
UART
Universal Asynchronous Receiver/Transmitter
UARTO
United Arab Republic Telecommunication Organization
UAS
Unified Antenna Structure
UAX
Unit Automatic Exchange
UBK
Unblock
UC
Unit Call
UDC
Universal Data Classification
UDEAC
Unión Aduanera Económica del Africa Central
UDMH
Unsymmetrical dimethyl Hydrozine
UDTS
Universal Data Transfer Service
UER
Union Europeenne Radiodiffusion (European Broadcasting Union)
UET
Unattended earth terminal
UFB
Unfit for Broadcast
UFT
Voice Frequency (VF) Telegraphy
UHF
Ultra-High Frequencies (Band 9; 300-3000 MHz)
UITP
International Union of Public Transport
UJT
Unijunction Transistor
ULCRA
Unión Latinoamericana y Caribeña de Radiodifusión (Latin American and Caribbean Radio Union)
ULK
Unlock
ULPC
Uplink power control system
UN
United Nations
UNCTAD
United Nations Conference on Trade and Development (UN)
UNDP
Development Program (UN)
UNDRO
Office of Disaster Relief Coordinator (UN)
UNEP
Environment Program (UN)
UNESCO
Educational, Scientific and Cultural Organization (UN)
UNI
User-network interface
Unicast
Data transmission from a single source to a single destination. Contrast with Multicast.
UNICODEC
Universal Coder/Decoder (TV Service)
UNIPEDE
(International union of Producers and Distributors of Electric Energy)
UNITAR
Institute for Training and Research (UN)
UNL
Unlatched
UPC
Universal Product Code
UPLS
Up-Front-Lump-Sum
UPS
Uninterruptible Power Supply or Uninterruptible Power System or Upper Performance Score
URM
Universal Restoration Manual
URSI
(International Union of Radio Science)
URTNA
(Union of National Radio and Television Organizations of Africa)
US
Unit Separator
USAID
United States Agency for International Development (USA)
USASAT
Generic name given to USA satellite networks
USB
Upper Side Band
USGS
United States Geological Survey (USA)
USISC
International Service Carriers (USA)
USS
Uplink Selector Switch
UST
"Unblock SPADE Terminal" command
UT
Universal Time
UTC
Universal Coordinated Time or Universal Time Clock
UTCA
Unconstrained Terminal Control Assignment
uW OR UW
uW Microwatt or UW Unique Word
UWER
Unique word error rate
UWL
Unique word loss
UWP
Unique word processor
UZrH
Uranium zirconium hydride reactor
V OR v
V Delta velocity or V Microvolt or V Potential or V Potential difference or V Electromotive force or V Volume or V Volt or v Velocity
V/D
Voice/Data
V/F
Voltage-to-Frequency
V1
Critical Speed
VA
Volt Ampere
VAB
Vehicle Assembly Building (Kennedy Space Center, Florida)
VAC
Volts AC
VADC
Attitude data control system motor drive voltage
VADCS
Attitude data control system motor drive voltage system
VADIS
Voice and Data Integrated System
VAJ
Feed forward term when firing axial thruster
VALV
Valve
VAN
Value Added Network
VAS
Value Added Service
VBD
Voice band data
VBTS
Beacon Tracking System motor drive voltage
VCC
Vehicle Command Count. Used with encryption
VCD
Valve Coil Driver
VCO
Voltage Controlled Oscillator
VCXO
Voltage Control Crystal Oscillator
VDA
Vapor Deposited Aluminum or Volume Discount Agreement
VDDA
Variable Destination Demand Assignment
VDT
Visual display terminal
VDU
Video Display Unit
VELCOR
Velocity Correction
VF
Voice Frequency
VFO
Variable Frequency Oscillator or Voice Frequency Oscillator
VFR
Visual Flight Rules (ICAO)
VFT
Voice Frequency Telegraph
VGA
Video Graphics Adapter
VHF
Very High Frequencies (Band 8)
VHRR
Very High Resolution Radiometer
VIAS
Voice Intelligibility Analysis Set
VID
Video
VIP
Versatile Information Processor
VIR
Vertical Interval Reference Signal
VIS
Video Short-term
VISSR
Visible and Infrared Spin Scan Radiometer
VITEAC
Video Transmission Engineering Advisory Committee (USA)
VITS
Verification International Test Signal
VLBI
Very Long Base Interferometer
VLF
Very Low Frequencies (Band 4)
VLR
Very Long Range
VLSI
Very Large Scale Integrations
VMOS
Vertical Metal-oxide Semiconductor
VN
Verification tests
Vne
Never exceed [a specific velocity]
VOC
Video Operations Center
VOD
Video on Demand
VODAS
Voice Operated Device Anti-Singing
VOGAD
Voice Operated Gain Adjusting Device
VOLNA
Mobile Satellite Network (Russian Federation)
VOM
Volt-ohm-milliammeter
VOR
VHF Omnidirectional Radio Range
VOW
Voice orderwire
VOX
Intersyllabic Voice Activated Carrier or Voice Activation (Voice-operated transmission) Voice-operated keyer
VPD
Variable Power Divider
VPF
Vertical Processing Facility (KSC)
VPN
Virtual Private Network
VPS
Variable phase shifters
VRE
Voice Recognition Equipment
VRJ
Feed Forward term when firing radial thruster
VRMS
Volts RMS
VSAT
Very Small Aperture Terminal
VSB
Vertical Sideband or Vestigial Sideband
VSDM
Variable slope delta modulation (encoding technique)
VSG
Video Stripchart Generator
VSM
Vestigial Sideband Modulation
VSP
Virtual Switching Point
VSWR
Voltage Standing Wave Ratio
VT
Vertical Tabulation
VTF
Via Terrestrial Facilities
VTPR
Vertical Temperature Profile Radiometer
VTR
Video Tape Recording
VTVM
Vacuum Tube Voltmeter (syn.: Valve Voltmeter)
Vu OR VU
Volume Unit
VVC
Voltage-Variable
W or w
W Electrical energy or W Microwatt or W Total Load (elec. eng.) or W Watt or W Weight (phys.) or w Weight per cubic meter (civ. eng.) or w OR W Work (phys.)
W/G
Waveguide
WAN
Wide Area Network
WARC
World Administrative Radio Conference
WATCHDOG
Timer for checking ACE operation
WATS
Wide area telephone service
WATSS
Wide Area Telephone Service System
WB
Wet Bulb or Wideband
WBD
Wideband Data (Channel)
WBEAF
Wideband Earth Station Antenna Feed
WBFM
Wideband Frequency Modulation
WBPA
Wideband Power Amplifier
WBS
Work Breakdown Structure
WBSARC
World Broadcasting Satellite Administrative Radio Conference
WBTVR
Wideband Video Tape Recorder
WDC
World Data Center (Rockets and Satellites)
WEFAX
Weather Facsimile
WESTAR
Western Union Telegraph Communication Satellite (USA)
WF
Weighing Function
WG
Waveguide
WGN
White gaussian noise
Wh
Watthour
WHO
World Health Organization (UN)
WISI
World Index of Space Imagery
WMC
World Meteorological Center
WMO
World Meteorological Organization (UN)
WMS
World Magnetic Survey
WORM
Write-Once Read-Many (memory storage)
WP
Working Party (CCIR/CCITT)
wpm OR WPM
Words Per Minute
WRTC
Working Reference Telephone Circuit
Ws
Wattsecond
WSMC
Western Space and Missile Center
WTG
Weighing
WWVB
National Bureau of Standards Radio Station (Boulder, Colorado)
WWW
World Weather Watch
X
Combined Services (CCITT) or Electro-negative atom or group, esp. halogen (chem.) or Reactance
X-band
frequency spectrum in the 8/7 GHz range or Loosely refers to satellites in the 8/7 GHz range
X-POL OR X-Pol
Cross-polarized
X-Strp OR X-STRP
Cross-strap
XCE
Transponder Command Electronics or Transponder Control Electronics
XDCR
Transducer
XIPS
Xenon Ion Propulsion Subsystem
Xmit
Transmit
XMTR
Transmitter
XPD
Cross-Polar Discrimination/Decoupling or Transponder
XPDR
Transponder
XPI
Cross Polar Interference or Cross Polarize Isolate
XSE/XDE
Transponder Sequencer and Driver Electronics
XSSF
Scanner Synch Failure
XTAL
Crystal
XTE
Transponder Telemetry Electronics
Y
Admittance (phys.)
z or Z
z Figure of merit (elec. eng.) or Z Impedance(phys.)
Z-CAL
Zero Range Calibration
ZRT
Zero Range Transponder
ZT
Zone Time