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3. Abbreviations and Acronyms
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a atto (10-18)
A amperes (current)
Å angstrom
AAR automatic alternate routing
AARTS automatic audio remote test set
ABR available bit rate
ABS alternate billing services
ABSBH average busy season busy hour
ac alternating current access information
ACC automatic callback calling
ACD automatic call distributor
ac-dc alternating current - direct current
ACG automatic call gap
ACH attempts per circuit hour
ACK acknowledge character
ACM address complete message
ACP action point
ACSB amplitude companded single-sideband
ACSE association control service element
ACTEL access telephone number
ACTL access customer terminal location
ACTS Advanced Communications Technology Satellite automated coin toll service
ACU automatic calling unit
A-D analog-to-digital
ADC analog-to-digital converter analog-to-digital conversion
ADCCP Advanced Data Communication Control Procedures
ADH automatic data handling
ADMD administration management domain
ADP automatic data processing
ADPCM adaptive differential pulse-code modulation
ADPE automatic data processing equipment
ADPSSO automatic data processing system security officer
ADS auxiliary data system
ADU automatic dialing unit
ADX automatic data exchange
AECS Aeronautical Emergency Communications System [Plan]
AERM alignment error rate monitor
AES Advanced Encryption Standard
AF audio frequency
AFC area frequency coordinator automatic frequency control
AFNOR Association Francaise de Normalisation
AFRS Armed Forces Radio Service
AGC automatic gain control
AGE aerospace ground equipment
AI artificial intelligence action indicator
AIC Automatic Intercept Center
AIG address indicator group address indicating group
AIM amplitude intensity modulation
AIN advanced intelligent network
AIOD automatic identified outward dialing
AIS automated information system alarm indication signal automatic intercept system
AITS acknowledged information transfer service
ASIC application-specific integrated circuits
AJ anti-jamming
AK data acknowledgement (see also “ACK”)
ALBO automatic line buildout
ALC automatic level control automatic load control
ALE automatic link establishment
ALGOL Algorithmic Computer Language
ALS application layer structure
ALU arithmetic and logic unit
A/m amperes per meter
AM amplitude modulation
AMA automatic message accounting
AMARC automatic message accounting recording center
AMAT automatic message accounting transmitter
AMC administrative management complex
AME amplitude modulation equivalent automatic message exchange
AMI alternate mark inversion [signal]
AM/PM/VSB amplitude modulation/phase modulation/vestigial sideband
AMPS automatic message processing system advanced mobile phone system
AMPSSO automated message processing system security officer
AMSC American Mobile Satellite Corporation
AMTS automated maritime telecommunications system
ANI automatic number identification
ANL automatic noise limiter
ANM answer message
ANMCC Alternate National Military Command Center
ANS American National Standard
ANSI American National Standards Institute
AP anomalous propagation application process
APAB all-primary / all-backup
APC adaptive predictive coding
APCO Association of Public Safety Communications Officials
APD, apd, a.p.d. avalanche photodiode
APDU application protocol data unit
API application program interface
APL average picture level
APND all-primary / no-backup
APOT additional point of termination
APK amplitude phase-shift keying
APS automatic protection switching
APSB all-primary / some backup
ARP address resolution protocol
ARPA Advanced Research Projects Agency [now DARPA]
ARPANET Advanced Research Projects Agency Network
ARQ automatic repeat-request
ARS automatic route selection
ARSR air route surveillance radar
ARU audio response unit
ASC AUTODIN Switching Center access service company access service coordinator
ASC-EC access service coordination exchange company
ASCII American Standard Code for Information Interchange
ASE application service element
ASG access service group
ASELP algebraic sum excited linear prediction
ASIC application-specific integrated circuits
ASN.1 abstract syntax notation one
ASP
aggregated switch procurement application service partadjunct service pointassignment source point
ASR access service request airport surveillance radar automatic send and receive
ASR NO access service request number
AT access tandem
ATACS Army Tactical Communications System
ATB all trunks busy
ATCRBS air traffic control radar beacon system
ATDM asynchronous time-division multiplexing
ATE automatic test equipment
ATIS Alliance for Telecommunications Industry Solutions [formerly ECSA]
ATM advanced testing method asynchronous transfer mode
ATN account telephone number
ATRS automated trouble reporting system
ATV advanced television
au astronomical unit access unit
AUI attachment unit interface
AUTODIN Automatic Digital Network
AUTOSEVOCOM Automatic Secure Voice Communications Network
AUTOVON Automatic Voice Network
AV audiovisual
AVD alternate voice/data
AWG American wire gauge
AWGN additive white Gaussian noise
AZ azimuth
b bit
B bel byte
BAAD band advance
balun balanced to unbalanced
basecom base communications
BASIC beginners' all-purpose symbolic instruction code
BCC block check character blocked calls cleared
BCD binary-coded decimal binary-coded decimal notation blocked calls delayed
BCI bit-count integrity
BCST broadcast
Bd baud
B8ZS bipolar with eight-zero substitution
bell BEL character
BER bit error ratio
BERT bit error ratio tester
BETRS basic exchange telecommunications radio service
BEX broadband exchange
BHMC busy hour minutes of capacity
BIB backward indicator bit
BIBR backward indicator bit received
BIBT backward indicator bit to be transmitted
BIBX backward indicator bit expected
BIC bearer identification code
BIH International Time Bureau
BIP bit interleaved parity
B-ISDN broadband ISDN
bi-sync binary synchronous [communication]
bit binary digit
BIT built-in test
BITE built-in test equipment
BIU bus interface unit
BLA blocking acknowledgment message
BLER block error ratio
BLO blocking message
BLR blocking/unblocking signal reception
BLS blocking/unblocking signal sending
BNF Backus Naur form
BOC Bell Operating Company
BPSK binary phase-shift keying
bpi bits per inch bytes per inch
b/s (formerly “bpi”)
bits per second
b/in (formerly “bps”)
bits per inch
BPSK binary phase-shift keying
BPSS basic packet switched service
BR bit rate
BRAN broadband radio access networks
BRI basic rate interface
BS base station
BSA basic serving arrangement
BSBH busy season busy hour
BSE basic service element basic serving element
BSI British Standards Institution
B6ZS bipolar with six-zero substitution
BSM backward setup message
BSN backward sequence number
BSNR backward sequence number received
BSNT backward sequence number of next signal unit to be transmitted
BSP Bell System Practices
BSS base station system basic service set
B3ZS bipolar with three-zero substitution
BTN billed telephone number billing telephone number
BW bandwidth
c centi (10-2)
CA communications assets
CACS centralized alarm control system
CAD call denial computer-aided design computer-aided drafting
CAG combined access group
CAI common air interface
CAISS common air interfaces for satellite systems
CAM computer-aided manufacturing
CAMA centralized automatic message accounting
CAN cancel character
CAP competitive access provider customer administration panel
CARS cable television relay service [station]
CAS centralized attendant services call associated signaling
CASE computer-aided software engineering computer-assisted software engineering
CATLAS centralized automatic trouble locating and analysis system
CATV cable TV
community antenna television
CB citizens band
CBA changeback-acknowledgment signal
CBAN Centrex billing account number
CBD changeback-declaration signal
CBMS computer based messaging system
CBN common bonding network
CBX computer branch exchange
CC connection confirm country code
CCBS completion of calls to busy subscribers
CCC clear channel capability
C2 command and control
C3 command, control and communications
C3CM C3countermeasures
C3I command, control, communications and intelligence
CCA carrier-controlled approach
CCD charge-coupled device
CCH connections per circuit per hour
CCIF International Telephone Consultative Committee [a predecessor to the CCITT]
CIP critical infrastructure protection
CCIR International Radio Consultative Committee
CCIS common-channel interoffice signaling
CCIT International Telegraph Consultative Committee [a predecessor to the CCITT]
CCITT International Telegraph and Telephone Consultative Committee {now ITU-T}
CCL continuous communications link
CCMDS common channel multipoint distribution system
CCO continuity check outgoing
CC-PIC customer changeable primary interexchange carrier
CCS hundred call-seconds common channel signaling
CCSA common control switching arrangement
CCS7 common channel signaling System #7
CCTV closed-circuit television
CCW cable cutoff wavelength
cd candela
CD collision detection, compact disk
CDA call data accumulator
CDF combined distribution frame cumulative distribution function
CDMA code-division multiple access
CDO community dial office
CDPD cellular digital packet data
CDPSK coherent differential phase-shift keying
CDR call detail recording
CD ROM compact disk read-only memory
CDT call data transmitter control data terminal
CDU central display unit
CE connection endpoint
C-E communications-electronics
CEF cable entrance facility
CEI comparably efficient interconnection connection endpoint identifier
CELP code-excited linear prediction
CEP circular error probable
CEPT Conference Europeennes des Administrations des Postes et des Telecommunications
CESID caller’s emergency service ID
CFA carrier facility assignment connecting facility assignment
CFE contractor-furnished equipment
CFL call failure
CGAP call gapping interval
CGB circuit group blocking acknowledgment message
CGC congestion control
cgs centimeter-gram-second
CGH charging message
CHOK choke network
ChR channel reliability
CI customer installation
CIAS circuit inventory and analysis system
CIC carrier identification code circuit identification code content indicator code
CIF common intermediate format
CIFAX ciphered facsimile
CIGRR common interest group on rating and routing
CINC commander-in-chief
ciphony ciphered telephony
CiR circuit reliability
CITEL Inter-American Telecommunications Commission
CK check bit
CKLT circuit link test
C/kT carrier-to-receiver noise density
CKTACT circuit activity
CKTID circuit identification number
CL connectionless
CLASS custom local area signaling service
CLC Carriers Liaison Committee
CLEI common language equipment identification
CLNS connectionless network service
CLP cell loss priority (bit)
cm centimeter
CMDF combined main distributing frame combined main distribution frame
CMDS centralized message data system
CMI coded mark inversion
CMIP Common Management Information Protocol
CMIS common management information service
CMOS complementary metal oxide substrate
CMR call modification request message
CMRR common-mode rejection ratio
CMRS Commercial Mobile Radio Service
CMS call management system
CNC concentrator
CNCC customer network control center
CNI calling number identification
CNP connection-not-possible signal
CNR carrier-to-noise ratio combat-net radio
CNS complementary network service connection-not-successful signal
C.O. central office connection oriented
COAM customer owned and maintained equipment
coax coaxial cable
COBOL common business oriented language
codec coder-decoder
COG centralized ordering group
COMINT communications intelligence
COMJAM communications jamming
compandor compressor-expander
COMPUSEC computer security
COMSAT Communications Satellite Corporation
COMSEC communications security
CONEX connectivity exchange
CONUS Continental United States
COP Committee of Principals
COR Council of Representatives
COT customer office terminal continuity message
COTS commercial off-the-shelf
CPAS cellular priority access services cellular priority access system
CPC call processing control calling party category circuit provision center
CPE customer premises equipment
cpi characters per inch
cpm counts per minute
CPNI calling party number identification
cps characters per second cycles per second [deprecated]
CPU central processing unit communications processor unit
C/R command/response field bit
CR channel reliability circuit reliability connection request
CRC cyclic redundancy check
CRITICOM Critical Intelligence Communications
CROM control read-only memory
CRR customer requested routing circuit reset reception
CRT cathode-ray tube
CRTS cellular radio telecommunications service
c/s cycles per second [deprecated]
CSA Canadian Standards Association
CSC circuit-switching center common signaling channel
CSES consecutive severely errored seconds
CSMA carrier sense multiple access
CSMA/CA carrier sense multiple access with collision avoidance
CSMA/CD carrier sense multiple access with collision detection
CST connection setup time
CSU channel service unit customer service unit
CTIA Cellular Telecommunications Industry Association
CTN cut-through operation
CTS clear to send
CTX Centrex ® [service] clear to transmit
CUG closed user group
CVD chemical vapor deposition
CVSD continuously variable slope delta [modulation]
cw carrier wave
continuous wave
CX composite signaling
cxr carrier
D* specific detectivity
d deci (101)
DA directory directory assistance
D( ) dispersion coefficient
da deka (10)
D-A digital-to-analog digital-to-analog converter
D/L downlink
DACS digital access and cross-connect system
DAI dial address incoming
DAO dial address outgoing
DAMA demand assignment multiple access
D-AMPS digital advanced mobile phone system
DARPA Defense Advanced Research Projects Agency [formerly ARPA]
dB decibel
dBa decibels adjusted
dBa(F1A) noise power measured by a set with F1A-line weighting
dBa(HA1) noise power measured by a set with HA1-receiver weighting
dBa0 noise power measured at zero transmission level point
DBAS database administration system
dBc dB relative to carrier power
dBm dB referred to 1 milliwatt
dBm(psoph) noise power in dBm measured by a set with psophometric weighting
DBMS database management system
dBmV dB referred to 1 millivolt across 75 ohms
dBm0 noise power in dBm referred to or measured at 0TLP
dBm0p noise power in dBm0 measured by a psophometric or noise measuring set having psophometric weighting
dBr power difference in dB between any point and a reference point
dBrn dB above reference noise
dBrnC noise power in dBrn measured by a set with C-message weighting
dBrnC0 noise power in dBrnC referred to or measured at 0TLP
dBrn(f1-f2) flat noise power in dBrn
dBrn(144-line) noise power in dBrn measured by a set with 144-line weighting
DBSN direct broadcast satellite network
dBv dB relative to 1 V (volt) peak-to-peak
dBW dB referred to 1 W (watt)
dBx dB above reference coupling
dc direct current
DC disconnect code
DCA Defense Communications Agency (now DISA)
DCE data circuit-terminating equipment digital channel equipment
DCF data communication function
DCL direct communications link
DCM digital carrier module
DCN data communications network
DCP data collection processor duplex central processor
DCPSK differentially coherent phase-shift keying
DCS Defense Communications System
DCT digital carrier trunk
DCTN Defense Commercial Telecommunications Network
DCWV direct-current working volts
DDD direct distance dialing
DDN Defense Data Network
DDS digital data service digital data system
DEL delete character
demarc demarcation point
demux demultiplex demultiplexing
dequeue double-ended queue
DES Data Encryption Standard
detem detector/emitter
DEW Distant Early Warning (Line)
DFI digital facility interface
DFSK double-frequency shift keying
DIA Defense Intelligence Agency
DIC digital interface controller
DID direct inward dialing
DIF digital interface frame
DIG digital integrity group
DIN Deutsches Institut für Normung
DIP dual in-line package
DIS Draft International Standard
DISA Defense Information Systems Agency {formerly DCA}
DISC disconnect disconnect command
DISN Defense Information System Network
DISNET Defense Integrated Secure Network
DIT directory information tree
DIU digital interface unit
DLA Defense Logistic Agency
DLC digital loop carrier Data Link control (layer)
DLCI data link connection identifier
DLY DL delay dial
DLE data link escape character
DLP Data Link protocol
DL TU digital line / trunk unit
DM degraded minute delta modulation disconnect(ed) mode
DMA Defense Mapping Agency direct memory access
DME distance measuring equipment
DMS Defense Message System
DNA Defense Nuclear Agency
DNHR dynamic nonhierarchical routing
DNI destination network identification
DNIC data network identification code
DNPA data numbering plan area
DNS Domain Name System
DO design objective
DoC Department of Commerce
DOC dynamic overload control
DOD Department of Defense direct outward dialing
DODD Department of Defense Directive
DODISS Department of Defense Index of Specifications and Standards
DOD-STD Department of Defense Standard
DOJ Department of Justice
DOS Department of State
DOT Department of Transportation
DOV data over voice
DP demarcation point dial pulse
DPCM differential pulse-code modulation
DPSK differential phase-shift keying
DQDB distributed-queue dual-bus [network]
DQPSK differential quadrature phase-shift keying
DR data receive
DRAM dynamic random access memory
DRS delayed release signal
DRSI destination station routing indicator
DS data speed digital signal direct support
DS0 digital signal 0
DS1 digital signal 1
DS1C digital signal 1C
DS2 digital signal 2
DS3 digital signal 3
DS4 digital signal 4
DSA dial service assistance
DSAM double-sided amplitude modulation
DSB double-sideband [transmission] Defense Science Board
DSB-RC double-sideband reduced carrier transmission
DSB-SC double-sideband suppressed-carrier transmission
DSC digital selective calling
DSCS Defense Satellite Communications System
DSDC direct services dialing capability
DSE data switching exchange
DSI digital speech interpolation
DSL digital subscriber line
DSN Defense Switched Network
DSn digital signal, level n
DSP digital signal processing
DSR data signaling rate
DSS data station selector direct station selection
DSSCS Defense Special Service Communications System
DS-SMF dispersion-shifted single-mode fiber
DSSR digital short range radio
DSSS direct sequence spread spectrum
DSTE data subscriber terminal equipment
DSU data service unit
DSX-n digital signal cross connect, level n
DTE data terminal equipment digital terminating equipment
DTG date time group
DTMF dual-tone multifrequency [signaling]
DTN data transmission network
DTO dial tone office
DTRS digital trunked radio system
DTS Diplomatic Telecommunications Service
DTU data transfer unit digital transmission unit
digroup terminal unitdirect to user
DU data unit
DUP data user part
DUV data under voice
DVL direct voice link
DWDM dense-wavelength division multiplexing
DXE [See DCE] data circuit-terminating equipment [See DCE] data circuit terminal equipment
DX signaling direct current signaling duplex signaling
E exa (1018)
E911 enhanced 911 (emergency service)
EA equal access expedited data acknowledgment message extended address field bit
EAS extended area service
EBCDIC extended binary coded decimal interchange code
Eb/N0 signal energy per bit per hertz of thermal noise
EBO embedded base organization
EBS Emergency Broadcast System
EBX electronic branch exchange
EC Earth coverage Earth curvature exchange carrier
ECA emergency changeover acknowledgement signal
ECC electronically controlled coupling enhance call completion
ECCKT exchange company cirtuit ID
ECCM electronic counter-countermeasures
ECM electronic countermeasures emergency changeover message
ECO emergency changeover order signal
ECPT electronic coin public telephone
ECSA Exchange Carrier Standards Association [now ATIS]
ECT exchange carrier tandem
ED expedited data
EDA electronic directory assistance
EDC error detection and correction
EDI electronic data interchange
EDP electronic data processing
EDTV extended-definition television
EE equipment engineering electrical engineering
EEI equipment-to-equipment interface
EF extended frame errored frame
EHF extremely high frequency
EIA Electronic Industries Association
eirp effective isotropically radiated power equivalent isotropically radiated power
800DB 800 Data Base
EIS Emergency Information System
EIT encoded information type
el elevation
ELECTRO-OPTINT
electro-optical intelligence
ELF extremely low frequency
ELINT electronics intelligence electromagnetic intelligence
ELSEC electronics security
ELT emergency locator transmitter
e-mail, E-mail, email
electronic mail
EMC electromagnetic compatibility
EMCON emission control
EMD equilibrium mode distribution
EME electromagnetic environment
emf electromotive force
EMI electromagnetic interference electromagnetic interference control
EMI/EMC electromagnetic interference and compatibility
EML expected measurement loss
EMP electromagnetic pulse
EMR electromagnetic radiation
EMR hazards electromagnetic radiation hazards
e.m.r.p. effective monopole radiated power equivalent monopole radiated power
EMS electronic message system
EMSEC emanations security
emu electromagnetic unit
EMV electromagnetic vulnerability
EMW electromagnetic warfare electromagnetic wave
ENQ enquiry character
EO end office
E.O. Executive Order
EOA&M engineering, operations, administration, and maintenance
EOC embedded operations channel
EOD end of data
EOF end of file
EOL end of line
EOM end of message
EOP end of program end output
EOS end-of-selection character
EOT end-of-transmission character end of tape
EOW engineering orderwire
EPL electronic switching system programming language
EPROM erasable programmable read-only memory
EPSCS enhanced private switched communications system
ERL echo return loss
ER link emergency response link
ERP, e.r.p. effective radiated power
ERR protocol data unit error
ES end system errored secondexpert system
ESC escape character enhanced satellite capability
ESF extended superframe
ESM electronic warfare support measures
ESMR enhanced specialized mobile radio
ESP enhanced service provider
ESS electronic switching system
ET exchange termination
ETB end-of-transmission-block character
ETGC Exchange Telephone Group Committee
ETS electronic tandem switching electronic translator system
ETSI European Telecommunications Standards Institute
ETX end-of-text character
EU end user
EW electronic warfare
EXCSA Exchange Carriers Standards Association facility accepted message
f femto (10-15)
f frequency
F farads (capacitance)
FAA Federal Aviation Administration
FACS facilities assignment and control system
FADU file access data unit
FAQ file Frequently Asked Questions file
FAX facsimile
FC functional component facility code
FCAP facility capability facility capacity
FCC Federal Communications Commission
FCM flow control message(s)
FCS frame check sequence
FDDI fiber distributed data interface
FDDI-2 fiber distributed data interface-2
FDHM full duration at half maximum
FDM frequency-division multiplex(ing)
FDMA frequency-division multiple access
FDT frame due time
FDX full duplex
FEBE far end block error
FEC forward error correction
FECC Federal Emergency Communications Coordinators
FED-STD Federal Standard
FEMA Federal Emergency Management Agency
FEP front-end processor
FEPS facility and equipment planning system
FET field effect transistor
FERF far-end receive failure
FIB forward indicator bit
FIC facility interface code
FID field identifier
FIFO first-in, first-out
FIP facility interface processor Federal Information Processing
FIPS Federal Information Processing Standards
FIR finite impulse response
FIRMR Federal Information Resources Management Regulations
FISINT foreign instrumentation signals intelligence
FISU fill-in signal unit
5ESS #5 Electronic Switching System
flops floating-point operations per secondstyle="mso-spacerun: yes">
FLMPTS Future Public Land Mobile Telecommunication Systems
FLTSATCOM Fleet Satellite Communications
FM frequency modulation
FO fiber optics
FOC final operational capability full operational capability fiber optics communications
FOCC Fiber Optics Coordinating Committee
FOT forward-transfer message
frequency of optimum traffic frequency of optimum transmission
FPDU frame relaying protocol data unit
FPGA field programmable gate array
FPIS forward propagation ionospheric scatter
ft/min feet per minute
fps foot-pound-second
FPS frames per second focus projection and scanning
FRJ facility reject message
FRP Federal Response Plan
FSDPSK filtered symmetric differential phase-shift keying
FSDU frame relaying service data unit
FSK frequency-shift keying
FSN forward sequence number
FSNR forward sequence number received
FSNX forward sequence number expected
FSS Fixed Satellite Service fully separate subsidiary
FT fiber optic T-carrier
FTAM file transfer, access, and management
FTF Federal Telecommunications Fund
FTR Federal Telecommunications Recommendation
ft/s feet per second
FTS Federal Telecommunications System Federal Telecommunications Service
FTS2000 Federal Telecommunications System 2000
FTSC Federal Telecommunications Standards Committee
FTSP Federal Telecommunication Standards Program
FTP file transfer protocol
FWHM full width at half maximum
FX fixed service foreign exchangeforeign exchange service
FX OPER foreign exchange trunk operation
g profile parameter
G giga (109)
GAN global area network
GAS special autonomous group
GBH group busy hour
GCT Greenwich Civil Time
GDF group distribution frame
GEO Geostationary Earth orbit Geosynchronous Earth orbit
GETS Government Emergency Telecommunications Service
GFE Government-furnished equipment
GGCL government-to-government communications link
GHz gigahertz
GII Global Information Infrastructure
GMT Greenwich Mean Time
GND ground
GOS grade of service
GOSIP Government Open Systems Interconnection Profile
GOTS government (-developed) off-the-shelf
GRP MOD group modulation
GRS reset circuit group message
GSA General Services Administration
GSM global system for mobile communications
GSTN general switched telephone network
G/T antenna gain-to-noise-temperature
GTP Government Telecommunications Program
GTS Government Telecommunications System
GUI graphical user interface
h hecto (102) Henry (inductance)Planck's constant
HALO high-altitude, long operation
HAPS high-altitude platform station
HBA hardware group blocking acknowledgment signal
HBUR hardware blocking/unblocking reception
HBUS hardware blocking/unblocking sending
HCS hard clad silica [fiber]
HCSDS high-capacity satellite digital service
HCTDS high-capacity terrestrial digital service
HDLC high-level data link control
HDTV high-definition television
HDX half-duplex [operation]
HE11mode the fundamental hybrid mode [of an optical fiber]
HEMP high-altitude electromagnetic pulse
HEO highly elliptical Earth orbit
HERF hazards of electromagnetic radiation to fuel
HERO hazards of electromagnetic radiation to ordnance
HERP hazards of electromagnetic radiation to personnel
HF high frequency human factors
HFDF high-frequency distribution frame
HGA hardware carrier group alarm
HGB hardware group blocking signal
HGU hardware group unblocking signal
HIPERLAN high-performance radio local area network
HLL high-level language
HML hunting multiline group number
HPC high probability of completion
HPF hunting preferential list
HSD high-speed data
HSSDS high-speed switched digital service
HU high usage
HV high voltage
Hz hertz
I current (amperes) information
IA International Alphabet [CCITT]
IAC initial alignment control
IAM initial address message
IAPP inter-access point protocol
I&C installation and checkout
IBOC in band, on-channel
IC integrated circuit interexchange carrier (also “IXC”)
ICAN individual circuit analysis
ICC incoming trunk circuit, Interstate Commerce Commission
ICCF Industry Carriers Compatibility Forum
ICI incoming call identification
ICIC Interexchange Carrier Industry Committee
ICN international closed user group number
ICNI integrated communications, navigation, and identification
ICSC Interexchange Customer Service Center
ICT interexchange carrier tandem
ICW interrupted continuous wave
ID identification identifier identity
IDDD International Direct Distance Dialing
IDF intermediate distribution frame intermediate distributing frame
IDL interface definition language
IDN integrated digital network
IDTV improved-definition television
IEC International Electrotechnical Commission
IEEE Institute of Electrical and Electronics Engineers
IES Industry Executive Subcommittee
IF intermediate frequency
I/F interface
IF1…IF6 interface 1…interface 6
IFF identification, friend or foe
IFIP International Federation for Information Processing
IFRB International Frequency Registration Board (now Radio Regulations Board )
IFRPS Intercity Facility Relief Planning System
IFS ionospheric forward scatter
IFx interface configuration x
IILC Information Industry Liaison Committee
IIR infinite impulse response
IITF Information Infrastructure Task Force
ILD injection laser diode
ILS instrument landing system
IM intensity modulation intermodulation interface module
IMA individual mobilization augmentee
I&M installation and maintenance
IMD intermodulation distortion
IMP interface message processor
IN intelligent network
IN/1, IN/1+, IN/2 intelligent network concepts [versions 1, 1+, 2]
INC Industry Numbering Committee international exchange carrier international carrier
INF information message
INFOSEC information systems security
INR information request message
INS inertial navigation system
INTELSAT International Telecommunications Satellite Consortium
INWATS Inward Wide-Area Telephone Service
I/O input/output [device]
IOC integrated optical circuit input-output controller
IOP input/output processor
IP Internet protocol intelligent peripheral interpersonal
IPA intermediate power amplifier
IPC information processing center
IPM
impulses per minute interference prediction model interpersonal messageinterruptions per minute
IPMS interpersonal messaging system
IPN interpersonal notification
IPRC Intellectual Property Rights Committee
IPTF Infrastructure Protection Task Force
in/s inches per second
ips interruptions per second
IPX Internet Packet Exchange
IQF intrinsic quality factor
IR infrared
IRAC Interdepartment Radio Advisory Committee
IRC international record carrier Interagency Radio Committee
IS international standard interim standard
ISB independent-sideband [transmission]
ISDN Integrated Services Digital Network
ISL intersatellite link
ISM industrial, scientific, and medical (applications)
ISO International Organization for Standardization
ISP Internet service provider
ISSI inter-RF subsystem interface
ISUP Integrated Services Digital Network user part integrated services user part
IT integrated test inactivity test information technology
ITA International Telegraph Alphabet
ITA-5 International Telegraph Alphabet Number 5
ITC International Teletraffic Congress independent telephone company
ITM installation, testing, and maintenance
ITS intelligent transportation system Institute for Telecommunication Sciences
ITSO International Telecommunications Satellite Organization
ITU International Telecommunication Union
I2 Next Generation Internet (also abbreviated “NGI”)
IVDT integrated voice data terminal
IXC interexchange carrier
JANAP Joint Army-Navy-Air Force Publication(s)
JCS Joint Chiefs of Staff
JMX jumbo group multiplex
jpeg Joint Photographic Experts Group (file format)
JS jack status
JSC Joint Steering Committee [now JTSSG] Joint Spectrum Center
JTC Joint Technical Committee
JTC3A Joint Tactical Command, Control and Communications Agency
JTIDS Joint Tactical Information Distribution System
JTRB Joint Telecommunications Resources Board
JTRS Joint Tactical Radio System
JTSCC Joint Telecommunications Standards Coordinating Committee
JTSSG Joint Telecommunications Standards Steering Group [formerly JSC]
k kilo (103) Boltzmann's constant
K coefficient of absorption kelvin
kb (or “Kbit”) 1000 bits (kilobit)
kb/s, or kbps kilobits per second
KDC key distribution center
KDR keyboard data recorder
KDT keyboard display terminal
kg kilogram
kg•m•s kilogram-meter-second
kHz kilohertz (1000 Hz)
km kilometer
k , k kilohm
KP keypulse
KSR keyboard send/receive device
kT noise power density
KTS key telephone system
KTU key telephone unit
wavelength
CO cutoff wavelength
L1 level 1, Layer 1 (physical/electrical interface)
L2 level 2, Layer 2 (signaling link functions)
L3 level 3, Layer 3 (signaling network functions)
L4 level 4 (ISDN user part)
LAC loop assignment center
LADT local area data transport
LAMA local automatic message accounting
LAN local area network
LAP-B Data Link Layer protocol [CCITT Recommendation X.25 (1989)] local access protocol, balanced
LAP-D link access procedure D link access protocol – D channel
laser light amplification by stimulated emission of radiation
LASINT laser intelligence
LATA local access and transport area
LBO line buildout
LBS load balance system
LC limited capability
LCD liquid crystal display
LCIE lightguide cable interconnection equipment
LCN local communication network
LD long distance
LDM limited distance modem
LEC local exchange carrier local exchange companies
LED light-emitting diode
LEGACT leg activity
LEO low Earth orbit
LERG local exchange routing guide
LF low frequency line finder
LFB look-ahead-for-busy [information]
LIDB line information data base
LIFO last-in, first-out
LLC logical link control [sublayer]
LLN line link network
LLSC link set control
l/m lines per minute
LMCS local multipoint communications system
LMDS local multipoint distribution system
LMF language media format
LMMS local message metering system
LMR land mobile radio
LNA launch numerical aperture
LOCAP low capacitance
LOF lowest operating frequency
loran long-range aid to navigation system long-range radio aid to navigation system
LOS line of sightloss of signal
LP linearly polarized [mode] log-periodic [array]
LPA linear power amplifier, loop-back acknowledgment message
LPC linear predictive coding
LPD low probability of detection
LPI low probability of interception
lpi lines per inch
lpm lines per minute
LP01 the fundamental mode (of an optical fiber)
LQA link quality analysis
LRAP long route analysis program
LRC longitudinal redundancy check
LRS line repeater station
LS line side
LSAC signaling link activity control
LSB lower sideband, least significant bit
LSC link state control
LSDA signaling data link allocation
LSI large scale integrated [circuit] line status indication
LSLA signaling link activation
LSLD signaling link deactivation
LSLR signaling link restoration
LSO local serving office
LSS local switching system
LSSU link status signal unit
LSTA signaling terminal allocation
LT the physical termination of the DSL at the network end
LTC line traffic coordinator
LTE line terminating equipment
LTF lightwave terminating frame
LUA link uninhibit acknowledgment
LUN link uninhibit message
LUF lowest usable high frequency
LULT line-unit-line termination
LUNT line-unit-network termination
LV low voltage
m meter milli (10-3)
M mega (106) maintenance modifier function bit
mA milliampere
MAC medium access control [sublayer]
MACOM major command
MAN metropolitan area network
MAP manufacturers' automation protocol
MAS mass announcement system
maser microwave amplification by the stimulated emission of radiation
M[ ] material dispersion coefficient
MAU medium access unit
MB message blocking
Mb/s also Mbps megabits per second
MCC maintenance control circuit master control center
MCDN microcellular data network
MCEB Military Communications-Electronics Board
MCM multicarrier modulation
MCS Master Control System
MCW modulated continuous wave
MCXO microcomputer compensated crystal oscillator
MD management domain mediation device
MDF main distribution frame
MDS message distribution system, multipoint distribution system
MDT mean downtime
MECAB multiple exchange carrier access billing
MEECN Minimum Essential Emergency Communications Network
MEO medium Earth orbit
MERCAST merchant-ship broadcast system
MESSPROC message processing
MET multibutton electronic telephone
MF medium frequency multifrequency [signaling] mediation function
MFD mode field diameter
MFJ Modification of Final Judgment
MFSK multiple frequency-shift keying
MFT metallic facility terminal
MGB maintenance group blocking signal
MGT mastergroup translator
MGU maintenance group unblocking signal
MHF medium high frequency
MHS message handling service message handling system
MHz megahertz
mi mile
MI machine interface
MIC machine interface code medium interface connector mutual interface chart
MII mobile information infrastructure
MILNET military network
MIL-STD Military Standard
min minute
MIP medium interface point
MIPS, mips million instructions per second
MIS management information system
MKS meter-kilogram-second
MLPP multilevel precedence and preemption
MLH multiline hunt
MLM multilongitudinal mode
MLPP multilevel precedence and preemption
MLT mechanical loop testing
MMDS multichannel multipoint distribution system
MMGT multimastergroup translator
MMITS modular, multifunctional information transfer system(s) [See SDR Forum]
MMUC minimum monthly usage charge
MMW millimeter wave
MMX mastergroup multiplex
MN mobile node
modem modulator-demodulator
modified AMI code modified alternate mark inversion code
mol mole
MOTIS message-oriented text interchange system
MOU minutes of use
mpeg Motion Picture Experts Group
MPN mode-partition noise
ms millisecond (10-3second) message store
MS mobile station
MSA metropolitan statistical area
MSB most significant bit
MSC media stimulated calling mobile switching center mobile services switching center
MSK minimum-shift keying
MSS Mobile Satellite Service mobile satellite system
MSTM maximum skew one-tenth maximum
MSU message signal unit
MTA message transfer agent
MTBF mean time between failures
MTBM mean time between maintenance
MTBO mean time between outages
MTBPM mean time between preventive maintenance
MTF modulation transfer function
MTIE maximum time interval error
MTP message transfer part
MTS message telecommunications service message transfer system
MTSE message transfer service element
MTSO mobile telephone switching office mobile telecommunications switching office
MTSR mean time to service restoral
MTTR mean time to repair
micro (10-6)
s microsecond
MUA maintenance group unblocking acknowledgment signal
MUF maximum usable frequency
muldem multiplexer/demultiplexer
MUX multiplex multiplexer
MUXing multiplexing
mv millivolt
mw microwave
mW milliwatt
MWI message waiting indicator
MWV maximum working voltage
n nano (10-9) refractive index
N. numeric characters, 0-9
N0 sea level refractivity spectral noise density
NA numerical aperture network aspects
NAC network administration center
NACSEM National Communications Security Emanation Memorandum
NACSIM National Communications Security Information Memorandum
NAK (also “NACK)”
negative-acknowledge character
NANA North American Numbering Administration
NANP North American Numbering Plan
NANPA North American Numbering Plan Administration
NASA National Aeronautics and Space Administration
NASNA National Association of State 9-1-1 Administrators
NASP network application service part
NATA North American Telecommunications Association
NA-TDMA North American ― Time Division Multiple Access
NATO North Atlantic Treaty Organization
NAVSTAR-GPS Navigational Satellite Timing and Ranging ─ Global Positioning System
NBEC non-Bell exchange company
NBFM narrowband frequency modulation
NBH network busy hour
NBRVF narrowband radio voice frequency
NBS National Bureau of Standards [now NIST]
NBSV narrowband secure voice
NC network channel network connection no current
NCC National Coordinating Center for Telecommunications
NCI network channel interface (code)
NCP network control point network control processor
NCS National Communications System
net control station
NCSC National Communications Security Committee
NCTE network channel terminating equipment
NDCC network data collection center
NDCS network data control system
NDER National Defense Executive Reserve
NDIS network driver interface specification
NEACP National Emergency Airborne Command Post
NEC National Electric Code ®
NECA National Exchange Carrier Association
NEF network element function
NEP noise equivalent power
NES noise equivalent signal
NETS Nationwide Emergency Telecommunications Service
NF noise figure
NFS Network File System
NGI Next Generation Internet [also abbreviated I2]
NGSO non-Geostationary orbit
NHN nonhunting number
NI network interface number identification
NIC network interface card
NICS NATO Integrated Communications System
NID network interface device network information database
NII National Information Infrastructure
NIOD network inward/outward dialing
NIST National Institute of Standards and Technology [formerly NBS]
NIU network interface unit
NLP National Level Program
nm nanometer
NMC network management center
nmi nautical mile
NNI network node interface
NOC network operations center
NOCS network operations center system
NOD network outward dialing
NOF Network Operations Forum
NORGEN network operations report generator
NOTIS network operations trouble information system
NOW number of WATS
Np neper
NP network pause
NPA numbering plan area
NPCI network protocol control information
NPN network provided number
NPNB no primary / no backup
NPR noise power ratio
N(r) receive sequence number
NRI net radio interface
NRM network resource manager
NRRC Nuclear Risk Reduction Center
NRZ non-return-to-zero
NRZI non-return-to-zero inverted
NRZ-M non-return-to-zero mark
NRZ-S non-return-to-zero space
NRZ1 non-return-to-zero, change on ones
NRZ-1 non-return-to-zero mark
ns nanosecond
N(s) send sequence number
NSA National Security Agency
NSC National Security Council network service center
NS/EP telecommunications
National Security / Emergency Preparedness telecommunications
NSP national signaling point
NSPMP network switching performance measurement plan
NSTAC National Security Telecommunications Advisory Committee
NTCN National Telecommunications Coordinating Network
NTMS National Telecommunications Management Structure
NT network termination physical termination of the DSL at the user end
NT1 network termination 1
NT2 network termination 2
NTI network terminating interface
NTIA National Telecommunications and Information Administration
NTN network terminal number
NTSC National Television Standards Committee National Television Standards Committee [standard]
NUL null character
NVIS near-vertical-incidence skywave
NXX 3-digit code identifying a central office exchange
O operations
ohm
OAM operations, administration and maintenance
OAMP operations, administration, maintenance, and provisioning
O&M operations and maintenance
OC operating company operations center optical carrier
OC-1 optical carrier Level 1
OC-N optical carrier Level N
OCC other common carrier
OCE other common carrier channel equipment
OCIS online customer information system
OCM office carrier module
OCR optical character reader optical character recognition
OCS originating call screening
OCU office channel unit orderwire control unit
OCVCXO oven controlled-voltage controlled crystal oscillator
OCXO oven controlled crystal oscillator
OD optical density outpulsed digitsoutside diameter
OEC other exchange company other exchange coordinator
OFC optical fiber, conductive
OFCP optical fiber, conductive, plenum
OFCR optical fiber, conductive, riser
OFDM orthogonal frequency division multiplexing
OFN optical fiber, nonconductive
OFNP optical fiber, nonconductive, plenum
OFNR optical fiber, nonconductive, riser
OGC outgoing trunk circuit
OI optical interface
OMAP operations, management, and administration part
OMB Office of Management and Budget
OMEG Operations and Maintenance Experts Group
ONA open network architecture
ONI operator umber identification
OPC originating point code
OPDU operation protocol data unit
opm operations per minute
OPMODEL operations model
OPS off-premises station operator services
OPSEC operations security
OPX off-premises extension
O/R originator/recipient
OR off-route service off-route aeronautical mobile service
ORL optical return loss
OS operations system
OSC oscillator
OSF operations system function
OSHA Occupational Safety and Health Administration
OSI open switch interval open switching interval Open Systems Interconnection
OSI-RM Open Systems Interconnection―Reference Model
OSP operator service provider
OSRI originating stations routing indicator
OSS operator service system operations support system
OSSN originating stations serial number
OTAM over-the-air management of automated HF network nodes
OTAR over-the-air rekeying
OTC operating telephone company
OTDR optical time domain reflectometer optical time domain reflectometry
OUTWATS Outward Wide Area Telecommunications Service
OW orderwire [circuit]
p pico (10-12)
P peta (1015) provisioning
PABX private automatic branch exchange
PACA-E enhanced priority access and channel assignment
PACS personal access communications system
PAD packet assembler/disassembler
PAL phase alternation by line
PAL-M phase alternation by line―modified
PAM pulse-amplitude modulation pass along message
PAMA pulse-address multiple access
p/a r peak-to-average ratio
PAR performance analysis and review
PARAMP parametric amplifier
par meter peak-to-average ratio meter
PAX private automatic exchange
PBER pseudo-bit-error-ratio
PBX private branch exchange
PC carrier power (of a radio transmitter) personal computer point code
PCAC point code allowed control
PCB power circuit breaker
printed circuit board
PCI protocol control information personal communications interface
PCM pulse-code modulation process control module
PCMCIA Personal Computer Memory Card Industry Association
PCME packetized circuit multiplication equipment
PCN Personal Communications Network
PCO peg count and overflow
PCPC point code prohibited control
PCR preventive cyclic retransmission
PCS Personal Communications Services plastic-clad silica [fiber]
PCSR parallel channels signaling rate
PD photodetector protocol discriminator
PDC personal digital cellular
PDM pulse delta modulation pulse-duration modulation
PDN public data network
PDS protected distribution system program data source
PDT programmable data terminal
PDU protocol data unit
PE emergency proving period peripheral equipment phase-encoded [recording]
PEP peak envelope power (of a radio transmitter)
pF picofarad
PF power factor
PFM pulse-frequency modulation
PHS personal handy phone system
PI protection interval
PIC plastic insulated cable presubscribed interexchange carrier
PIN personal identification number(s)
ping packet Internet groper
PIV peak inverse voltage
PLA programmable logic array
PLL phase-locked loop
PLN private line network
PL/I programming language 1
PLR pulse link repeater
PLS physical signaling sublayer
pm phase modulation
PM
mean power preventive maintenance protocol machinepulse modulation
PMB pilot-make-busy [circuit]
PMO program management office
PNNI private network-to-network interface (signaling)
POC point of contact processor outage control
POI point of interface
POP point of presence
POSIX Portable Operating System Interface for Computer Environments
POT point of termination
POTS plain old telephone service
PP polarization-preserving [optical fiber]
P-P peak-to-peak [value]
P/P point-to-point
PPDU presentation protocol data unit
PPM pulse-position modulation
pps pulses per second
PR pulse rate
PREMIS premises information system
PRF pulse-repetition frequency
PRESUB presubscription
PRI primary rate interface
PRILOC primary location
PRM pulse-rate modulation
PRMD private management domain
PROM programmable read-only memory
PROVINT provisioning interval
PRR pulse repetition rate
PRSL primary area switch locator
PS permanent signal
PSAP public service answering point presentation service access point
PSDN public switched digital network
PSDS public switch digital services
psi pounds [force] per square inch
PSK phase-shift keying
PSN public switched network
PSPDN public switched packet data network
p-static precipitation static
PSTN public switched telephone network
PSWAC Public Safety Wireless Advisory Committee
PSWN public safety wireless network
PTE path terminating equipment
PTF patch and test facility
PTM pulse-time modulation
PTT postal, telephone, and telegraph push-to-talk [operation]
PTTC paper tape transmission code
PTTI precise time and time interval
PU power unit
PUC public utility commission public utilities commission
PV parameter value
PVC permanent virtual circuit polyvinyl chloride [insulation]
pW picowatt
PWM pulse-width modulation [deprecated]
pWp picowatt, psophometrically weighted
pWp0 picowatts, relative to a 0TLP
PWT Personal Wireless Telecommunications
pX peak envelope power (in dB)
PX peak envelope power peak envelope power (in watts)
pY mean power [in dB]
PY mean power [in watts]
pZ carrier power [in dB]
PZ carrier power [in watts]
Q speech-to-speech-correlated-noise ratio
QA quality assurance
QAM quadrature amplitude modulation
QC quality control
QCIF quarter common intermediate format
QMR qualitative material requirement
QOS quality of service
QPSK quadrature phase-shift keying
QRC quick reaction capability
QRS quasi-random signal
QRY query
QSS quality surveillance system
QTY quantity
QSTAG Quadripartite Standardization Agreement
R
resistance (ohms) ring ring conductor route service
R1 ring ring conductor
racon radar beacon
rad radian radiation absorbed dose
radar radio detection and ranging
RADHAZ electromagnetic radiation hazards
RADINT radar intelligence
RAM random access memory reliability, availability, and maintainability
R&D research and development
RATT radio teletypewriter system
RBOC Regional Bell Operating Company
RbXO rubidium-crystal oscillator
RC
reception control reflection coefficient resource controller retransmission counter
RCC radio common carrier
RCM reject connect modify message remote carrier module
RCVR receiver
RDES remote data entry system
RDS radio digital system
RDT radio digital terminal
RDF radio direction-finding
RE return error remote entry
REA Rural Electrification Administration
REC receiver
REJ reject
REL release message
REM remote equipment module
REN ringer equivalency number
RES radio equipment and systems resume message
RGB red-green-blue
rf radio frequency range finder
RFI radio frequency interference
RFP request for proposal
RFQ request for quotation
RH relative humidity
RHR radio horizon range
RI routing indicator
RID response ID
RISC reduced instruction set chip
RJ registered jack reference number reject
RJE remote job entry
RL restoral limit
RLC release complete message
RLMS return loss measuring set
RLSD released message
rms root-mean-square [deviation]
RNR receive not ready
RO read only receive only reorder
ROA recognized operating agency
ROH receiver off-hook
ROC required operational capability
ROM read-only memory
ROSE remote operations service element protocol
RP restoration priority
RPI radio port intermediary
RPLY reply
rpm revolutions per minute
RPM rate per minute
rps revolutions per second
RPT radio personal terminal
RQ repeat-request
RR receive ready repetition rate return result
RSA rural service area
RSC reset-circuit message
RSCM reset confirmation message
RSM remote switching module signaling-route-set-test message
RSL received signal level
RSRM reset request message
RSRT signaling route set test control
RSS remote switching system
rss root-sum-square
RST reset circuit
RT radio termination
R/T real time
RTA remote trunk arrangement
RTA transfer allowed control
RTB retransmission buffer
RTC restart confirmation
RTCC transfer-controlled control
RTM remote test module
RTPC transfer prohibited control
RTR restart request
RTRC transfer-restricted control
RTS request to send
RTTY radio teletypewriter
RTU remote terminal unit
RTX request to transmit
RVA reactive volt-ampere
RVWG Reliability and Vulnerability Working Group
RWI radio and wire integration
RX receive receiver
RZ return-to-zero [code]
s second
S supervisory function bit
SABME set asynchronous balanced mode extended
SAC service access code
SAL service affecting limit
SAM subsequent-address message
SAP service access point
SAPI service access point identifier
SAR special access request
SARTS switched access remote test system
SAS switched access services
SASE specific application service elements
SBR subsystem backup routing
SBRC subsystem backup routing control
SBUR software blocking/unblocking reception
SBUS software blocking/unblocking sending
SC service code standard coding
SCC specialized common carrier switched control center
SCCP signaling connection control part
SCCS switched control center system
SCE service creation environment
SCEG experts group on speech coding
SCF service control facility
SCP service control point
SCPC single channel per carrier
SCR semiconductor-controlled rectifier silicon-controlled rectifier
SCRT service class routing
SCSR single channel signaling rate
SCU selector control unit
SDL Specification and Description Language
SDLC synchronous data link control
SDM space-division multiplexing [deprecated]
SDN software-defined network
SDO standards development organization
SDR software-defined radio
SDR Forum Software Defined Radio Forum [formerly MMITS]
SDU service data unit
SECAM systeme electronique couleur avec memoire sequential couleur avec memoire
SECDEF Secretary of Defense
SECLC secondary location
SECLOC secondary location
SECORD secure voice cord board
SECTEL secure telephone
SECTLV secondary transmission level point
SEG experts group on security
SEL selector
SES satellite earth station(s) severely errored second(s)
SETAMS systems engineering, technical assistance, and management services
SEVAS Secure Voice Access System
S-F store-and-forward
SF single-frequency [signaling] status field
SG study group
SGDF supergroup distribution frame
S/H sample and hold
SHA sidereal hour angle
SHARES Shared Resources (SHARES) HF Radio Program
SHF super high frequency
SI International System of Units service indicator status indicator
SIB status indication “B” (“busy”)
SID sudden ionospheric disturbance
SIE status indication “E” (“Emergency Alignment”)
SIF signaling information field signal information field
SIGINT signals intelligence
SIM subscriber identity module
SINAD signal-plus-noise-plus-distortion to noise-plus-distortion ratio
SIO service information octet
SIT special information tone
S( ) chromatic dispersion slope
SLC signaling link code
SLD superluminescent diode [see superluminescent LED ]
SLI service logic interpreter
SLM signaling link management single longitudinal mode
SLP service logic program
SLS signaling link selection code
SLTA signaling link test message acknowledgment
SLTC signaling link test control
SLTM signaling link test message
SMAS switched maintenance access system
SMDF subscriber main distribution frame subscriber main distributing frame
SMDR station message-detail recording
SMF single-mode fiber
SMH signaling message handling
SMR specialized mobile radio
SMS service management system
SMSA standard metropolitan statistical area
SMTP simple mail transport protocol
SNA shared network arrangement
SNI signaling network interworking
SNMP simple network management protocol
SNR signal-to-noise ratio subsystem-normal-routing (message)
SOH start-of-heading character
SOM start of message
sonar sound navigation and ranging
SONET synchronous optical network
SOP standard operating procedure
SOR start of record subsystem-out-of-service-request message
SOW statement of work
SP signal processor signaling point
SPC stored-program control signaling point code
SPCS stored-program control system
SPDU session protocol data unit
SPE synchronous payload envelope
SPNB some-primary / no backup
SPOT secondary location point of termination signaling point of termination
SPRC signaling process control
SPS signaling protocol and switching
SPSB some-primary / some backup
(S+N)/N signal-plus-noise-to-noise ratio
sr steradian
SR service request
S/R send and receive
SRC service request confirmation
SRM signaling route management
SRO standards related organization
SRT subsystem routing status test message
SRTC subsystem-routing status test control
SSB single-sideband [transmission]
SSBAM single-sideband amplitude modulation
SSB-SC single-sideband suppressed carrier [transmission]
SSD second start dial
SSF subservice field
SSN station serial number subsystem number
SSP
service switching point service signaling point signal service point subsystem-prohibited message
SSPC subsystem-prohibited control
SSR side-mode suppression ratio
SS7 Signaling System No. 7
SST subsystem-status-test message service transfer point
SSTC subsystem status test control
SSUPS solid-state uninterruptible power system
ST end-of-pulsing signal
start signal
STALO stabilized local oscillator
STANAG Standardization Agreement [NATO]
STD subscriber trunk dialing state transition diagram
STFS standard time and frequency signal [service] standard time and frequency service
STL standard telegraph level studio-to-transmitter link
STM signaling traffic management
STP standard temperature and pressure signal transfer partsignal transfer point
STS synchronous transport signal
STS-1 synchronous transport signal level 1
STS-n synchronous transport signal level n
STS POH synchronous transport signal path overhead
STS PTE synchronous transport signal path terminating equipment
STU secure telephone unit
STX start-of-text character
SU signaling unit signal unit
SUB substitute character
SUPERNET Sjared Im;ocemsed {erspma; Radop Metwprl
SUS suspend message
SVC switched virtual circuit
SWR standing wave ratio
SX simplex signaling
SXS step-by-step switching system step-by-step system
SYN synchronous idle character
SYNTRAN synchronous transmission
SYSGEN system generation
T tera (1012) tip tip conductor
T1 1st ANSI Telecommunications Standards Committee
tip tip conductor
T1AG T1 Advisory Group
T1A1 T1 committee on Performance and Signal Processing
T1E1 T1 committee on Interfaces, Power and Protection for Networks
T1EDH T1 committee on Electronic Data Handling
T1M1 Internetwork Operations, Administration, Maintenance, and Provisioning (IOAM&P)
T1P1 T1 committee on Wireless/Mobile Services and Systems
T1S1 T1 committee on Services, Architectures, and Signaling
T1X1 T1 committee on Digital Hierarchy and Synchronization
TADIL tactical data information link
TADIL-A tactical data information link-A
TADIL-B tactical data information link-B
TADS teletypewriter automatic dispatch system
TADSS Tactical Automatic Digital Switching System
TAI International Atomic Time
TASC telecommunications alarm surveillance and control (system)
TASI time-assignment speech interpolation
TAT trans-Atlantic telecommunication (cable)
TB transmission buffer
TC toll center technical committee transport connection
TCAP transaction capability control part (of SS7) transaction capabilities application part
TCAS T-carrier administration system
TCB trusted computing base
TCBC changeback control
TCC telecommunications center
TCCF Tactical Communications Control Facility
TCF technical control facility transfer controlled
TCIC trunk circuit identification code
TCIF Telecommunication Industry Forum
TCL terminal coupling loss
TCLw weighted terminal coupling loss
TCM time-compression multiplexing
TCOC changeover control
TCP transmission control protocol
TCPAP transaction capabilities control part
TCPIP Transmission Control Protocol/Internet Protocol
TCRC controlled rerouting control
TCS trusted computer system
TCSP tandem cross section program
TCU teletypewriter control unit
TCVXO temperature compensated-voltage controlled crystal oscillator
TCXO temperature controlled crystal oscillator
TD time delay transmitter distributor
TDAS traffic data administration program
TDD telecommunications device for the deaf time division duplex
TDEA Triple Data Encryption Algorithm
TDM time-division multiplexing
TDMA time-division multiple access time division multiplex
TDR traffic distribution request
TE transverse electric [mode] terminal equipment
TED trunk encryption device
TEI terminal endpoint identifier
TEK traffic encryption key
TEM transverse electric and magnetic [mode]
TEMPEST compromising emanations
TEMS telecommunications management system
TERM terminal
TFA transfer-allowed signal
TFC transfer-controlled signal
TFLAP T-carrier fault-locating applications program
TFMI traffic mix information
TFP transfer-prohibited signal
TFPC Toll Fraud Prevention Committee
TFR transfer-restricted (signal)
TFRC forced rerouting control
TFS trunk forecasting system
TFTS Terrestrial Flight Telephone System
TGID trunk group identification
TGM trunk group multiplexer
TGSN trunk group serial number
THD total harmonic distortion
THF tremendously high frequency
THz terahertz
TIA Telecommunications Industry Association
TIE time interval error
TIFF tag image file format
TIP terminal interface processor
TK response timer
TL Transport Layer transmission level
TLAC link availability control
TLN trunk link network
TLP transmission level point
TL/PVC Transport Layer / permanent virtual circuit
TL/SVC Transport Layer / switched virtual circuit
TLV transmission level
TM transverse magnetic [mode] transmission and multiplexing
TMD trunk main distributing
TMDF trunk main distributing frame
TMN telecommunications management network
TMS time-multiplexed switch
TNDS total network data system
TNOP total network operations plan
TP test pad
test pattern toll point
TPDU transport protocol data unit
TPT test progress tone
TQ transmission quality
TQTF Transmission Quality Task Force
TRA traffic routing and administration
TRANSEC transmission security
TRC transverse redundancy check
TRCC signaling link congestion control
TRD timed release disconnect
TRF tuned radio frequency
TRFTYP traffic type
TRI traffic routing information
TRI-TAC tri-services tactical [equipment]
TRM termination
TRM TYP termination type
TRMTR also Xmtr transmitter
TS trunk side
TSB Telecommunication Standardization Bureau
TSC technical subcommittee
TSFC signaling traffic flow control
TSI time-slot interchange
TSK transmission security key
TSP Telecommunications Service Priority [system] traffic service position
TSPS traffic service position system
TSR
telecommunications service request terminate and stay resident trunk service record testing services request
TSRC signaling routing control
TSS trunk servicing system
TTC Telecommunication Technology Committee (Japanese)
TTL transistor-transistor logic
TTTN tandem tie trunk network
TTY teletypewriter
TTY/TDD telecommunications device for the deaf
TUP telephone user part
TV television
TW traveling wave
TWT traveling wave tube
TWTA traveling wave tube amplifier
TWX® teletypewriter exchange service
TX transmit transmitter
TXC transmission control
U unnumbered
UA unnumbered acknowledgment user agent
UAV unmanned air vehible
UBA unblocking-acknowledgment message
UBL unblocking message
UCC universal commercial code
UCD uniform call distribution
UDP User Datagram Protocol
UHF ultra high frequency
UI unit interval unnumbered information
UIM user identity module
UIS user-in-service
UITS unacknowledged information transfer service
ULF ultra low frequency
U/L uplink
UNI unidirectional user-network interface
UP user part
UPN user provided number
UPS uninterruptible power supply
UPT Universal Personal Telecommunications [service]
UPTAN Universal Personal Telecommunications access number
URL universal routing locator
USB upper sideband universal serial bus
USBS user signaling bearer service
USDA U.S. Department of Agriculture
USFJ U.S. Forces, Japan
USFK U.S. Forces, Korea
USNO U.S. Naval observatory
USOC universal service order code
USR user-to-user information message
USTA U.S. Telephone Association [formerly USITA]
UT Universal Time
UTC Coordinated Universal Time
uv ultraviolet
UWCC Universal Wireless Communications Consortium
V volt normalized frequency
VA value-added [network service] volt-ampere
Vac volts, alternating current
VAN value-added network
VAR value added reseller
VARISTAR variable resistor
vars volt-amperes reactive
VC vacant code virtual circuit
VCC virtual channel connection
VCL virtual channel link
VCO voltage-controlled oscillator
VCXO voltage-controlled crystal oscillator
V/D voice/data
Vdc volts, direct current
VDCL virtual data link capability (protocol)
VDU video display unit visual display unit
VER version identification version number
VF voice frequency
VFCT voice frequency carrier telegraph
VFCTG voice frequency carrier telegraph
VFDF voice frequency distribution frame
VFO variable-frequency oscillator
VFTG voice-frequency telegraph
VHF very high frequency
VITS vertical interval test signal
VIU voiceband interface unit
VLAN virtual local area network
VLF very low frequency
V/m volts per meter
VNL via net loss
VNLF via net loss factor
vocoder voice-coder
VOD video on demand voice over data (link)
vodas voice-operated device anti-sing
vogad voice-operated gain-adjusting device
VoIP voice over Internet [protocol]
volcas voice-operated loss control and echo/signaling suppression
vox voice-operated relay circuit voice operated transmit
VRC vertical redundancy check
VSAT very small aperture terminal
VSB vestigial sideband [transmission] vestigial sideband [modulation]
VSELP vector sum excited linear prediction
VSM vestigial sideband modulation
VSWR voltage standing wave ratio
VT virtual terminal virtual tributary
VTU video teleconferencing unit
vu volume unit
W Watt
WADS wide area data service
WAIS Wide Area Information Server
WAN wide area network
WAND wireless ATM network demonstrator
WARC World Administrative Radio Conference
WATM wireless asynchronous transfer mode
WATS Wide Area Telecommunications Service Wide Area Telephone Service
WAWS Washington Area Wideband System
WMCCS Worldwide Military Command and Control System
WDM wavelength-division multiplexing
WG working group
WHSR White House Situation Room
WI wink
WIN wireless information network WWMCCS Intercomputer Network
WITS Washington Integrated Telecommunications System
WLAN wireless local area network
WLL wireless local loop
wmATM wireless mobile ATM
WORM write once, read many times
wpm words per minute
wps words per second
WPBX wireless PBX
WPS Wireless Priority Service (Program)
WRU who-are-you [character]
WS workstation
W3C World Wide Web Consortium
WTN working telephone number
wv working voltage
WVDC working voltage direct current
WWAN wireless wide area network
WWDSA worldwide digital system architecture
WWMCCS Worldwide Military Command and Control System
WWW World Wide Web
XB crossbar
XBT crossbar tandem
XID exchange identification
XMIT transmit
XMSN transmission
XMTD transmitted
Xmtr also TRMTR
transmitter
XO crystal oscillator
XOFF transmitter off
XON transmitter on
XT crosstalk
XTAL crystal
Z impedance Zulu time
ZBTSI zero-byte time slot interchange
ZD zero defects
Zo characteristic impedance
0TLP zero transmission level point
This HTML version of Telecom Glossary 2K was last generated on Fri Aug 3 15:37:18 MDT 2001. References can be found in the Foreword.
