Search here for communications (and some other) related acronyms and terms.
Link to the Glossary A - D
Link to the Glossary E - K
Link to the Glossary L - R
Link to the Glossary S - Z
For computer and internet technology definitions - try Webopedia
Another good site for more general definitions is Wikipedia
If you do not find what you are looking for, or have a question
or a suggestion, please contact us by EMail
Acronyms A - D
Scroll down to find the acronym or term you want defined (or use Control-F to search the page)
AC
Alternating Current
ACTS
Advanced Communications Technologies and Services
ADR
Alternative Dispute Resolution
ADPCM
Adaptive Differential Pulse Code Modulation. An encoding technique, similar to PCM, for digitising analogue voice signals at a reduced rate of 32 kBit/s
AM
Amplitude Modulation. A method for impressing information on a carrier by varying its amplitude
AMPS
Advance Mobile Phone System - cellular system standard used in the USA
API
Application Programmer's Interface
ATM
Asynchronous Transfer Mode
ATDMA
Advanced/Adaptive Time Division Multiple Access Project
ARQ
Automatic Repeat reQuest. A method of error connection whereby the receiver asks the transmitter to resend a block or frame found to contain errors
ASCII
Pronounced "asky". The American Standard Code for Information Interchange. The US version of the ISO 7-bit data code, usually transmitted in 8-bit characters, the additional bit being an (odd or even) parity bit
AVL
Automatic Vehicle Location - various land-mobile and satellite systems are used to establish the location of a vehicle or person
back to index
BANDWIDTH
The size of the frequency range a communication channel can carry
BASE STATION
The transmitter/receiver and associated equipment at a fixed location
BAUD
Unit of signalling speed - expressed as the number of discrete condition or signal events per second
BCS
Base Station Controller
BER
Bit Error Rate
BFWA
Broadband Fixed Wireless Access
BIT
Binary digIT - a unit of information (Zero or One)
BPM
Business Process Management
BPS
Bits Per Second
BRAN
Broadband Access Network
BYTE
Eight BITs forming a unit of data (usually one character - a letter, number or symbol)
back to index
CAI
Common Air Interface - a standard so that terminals can be used on any networks
CARRIER
An electromagnetic signal which is used as a medium for an information channel. The carrier's fundamental property such as frequency or amplitude is "modulated" (changed in some systematic way) by the information signal which is being transported)
CBS
Common Base Station - a shared wide-area repeater base station
CCIR
Committee Consultatif International Radio Communication
CCITT
The International Telephony and Telegraphy Consultative Committee, which is part of the International Telecommunications Union, an agency of the United Nations. The principal members of CCITT are the world's public communication authorities (PTO's)
CDLC
Cellular Data Link Control. A Proprietary protocol for modems which are to be used over a radio link. CDLC employs elaborate error correcting schemes to compensate for the high error rates of radio links
CDM
Credit and Debt Management
CDMA
Code Division Multiple Access - Spread Spectrum, where users share the same time and spectrum and are separated by different unique coding.
CELLULAR
A technique used in mobile radio telephony to use the same radio spectrum many times in one network. Lower power radio transmitters are used to cover a limited area or "cell" such that the frequencies in use can be re-used in other parts of the network
CEPT
European Conference of Postal & Telecommunications Administrations. CEPT is an association of European PTTs (Postal Telephone and Telegraph Administrations) and network operators from 18 countries
CLI
Calling Line Identification
COMMUNITY REPEATER
A repeater base station which is shared by several separate groups of users
CORDLESS
In the world of mobile communications, a voice communications system in which the user is not continuously moving and which is limited in range.
CPE
Customer Premises Equipment
CPS
Carrier Pre-Selection
CSMA/CD
Carrier Sense Multiple Access/Collision Detection; one of the major classes of media access technology,
used in LANs, particularly Ethernet. It is specified in OSI Standard ISO 8802/3, based upon the work of IEEE committee 802.3
CT1
Cordless Telephone (1st Generation) in use only in the UK - operates in the HF / low VHF bands using analogue technology
CT2
Cordless Telephone (2nd Generation) - a digital standard for cordless telephones
CTCSS
Continuous Tone Controlled Signalling System (or Sub-audio Squelch)
back to index
dB
Decibel - a measure of the change or difference in levels between two signals
DC
Direct Current
DCS - Digital Controlled Squelch.
A digital variant of the CTCSS signalling. Transmitted as a low speed digital signal alongside voice.
DCS1800
ETSI standard based on GSM for cellular networks in the 1.8 GH\z to 2 GHz band. Adopted for UK PCN
DECT
Digital European Cordless Telephone. A pan-European standard for cordless systems designed to operate in a wide range of applications
DIGITAL
Used to describe a signal which changes state in discrete increments
DTE
Data Terminal Equipment
DTMF
Dual Tone Multi-Frequency
DUPLEX
Simultaneous two-way sending and receiving
Acronyms E - K
Scroll down to find the acronym or term you want defined (or use Control-F to search the page)
back to index
EDI
Electronic Data Interchange
EEA
The European Association representing the Electronics, Telecommunications and Business Equipment Industries
EIA
The US Electronic Industries Association is an Accredited Standards Committee of ANSI (American National Standards Institute) responsible for some Physical Layer standards e.g. RS 232
EMC
Electromagnetic Compatibility
EPIRB
Emergency Position Indicating Radio Beacon
ERC
European Radiocommunications Committee - the main CEPT committee looking after radio matters
ERMES
European Radio MEssaging System - an ETSI digital paging standard that never took off
ERO
European Radio Office - website
permanent secretariat within ERC
ERP
Effective Radiated Power. The product of the power supplied to an antenna and its gain relative to a half wave dipole in a given direction
E-TACS
Extended Total Access Communications System. The extension to TACS by the addition of further channels
ETHERNET
A type of local area network based upon CSMA/CD technology - 10MB/s Ethernet was a joint development by Digital Equipment Corporation, Intel and Xerox
ETSI
European Telecommunications Standards Institute - website
an autonomous body formed in 1988 by the European Commission and CEPT to undertake standards writing activities. The membership of ETSI is open - currently 135 organisations including national administrations, public network operators, manufacturers, users and research bodies
EU
European Union
back to index
FDD
Frequency Division Duplex
FDMA
Frequency Division Multiple Access. The process of dividing up the available spectrum into channels of different frequencies
FEC
Forward Error Correction. A technique for error correction which does not require the retransmission of data from the transmitter
FFSK
Fast Frequency Shift Key. Sub carrier modulated signalling system operating at 1,200 and 1,800 band that can be used for data transmission
FM
Frequency Modulation - variation of the frequency of a carrier wave in response to a modulating signal
FSK
Frequency Shift Keying - sub-carrier modulated signalling system that can be used for data transmission
FSS
Fixed Satellite Service
FWA
Fixed Wireless Access
back to index
GHz
Gigahertz
GMSK
Gaussian Minimum Shift Keying. Another refinement of PSK which minimises adjacent channel interference
GPRS
General Packet Radio Service
GROUNDPLANE
The horizontal surface required for propagation from an antenna. Usually the earth's surface
GSM
Global System for Mobile Communications - originally a European cellular standard from ETSI now used world-wide
HDLC
High Level Data Link Control. A CCITT standard for the frame structure and protocol for the exchange of data at the Data Link level
HF
High Frequency - (3 to 30 MHz)
HYPERLAN
High Performance Radio Local Area Networks
Hz
Hertz - A frequency of one cycle per second
IA5
International Alphabet no. 5. The ISO equivalent of ASCII
IEC
International Electro technical Commission
IP
Internet Protocol
ISDN
Integrated Services Digital Network. An internationally agreed public network offering switched end-to-end digital services for voice and data
ISM
Industrial Scientific and Medical - the use of radio for non-communication purposes such as microwave heating and radiography
ITU
International Telecommunications Union
JPEG
Joint Photographic Experts Group
KHz
Kilohertz - 1000 cycles per second
Acronyms L - R
Scroll down to find the acronym or term you want defined (or use Control-F to search the page)
back to index
LAN
Local Area Network. A network which spans a limited geographical area (usually within one building or site) and interconnects a variety of computers and terminals
LF
Low Frequency (30-300kHz)
LLU
Local Loop Unbundling - More
LPC
Linear Predictive Coding. A speech digitising technique which extracts features from the speech pattern and sends the features to the receiving end where the original speech is synthesized. Used because lower bit rates for good quality speech transmission can be achieved relative to conventional digitising such as PCM
LPD
Low Power Devices - generally small transmit (a few 100mw or less) and/or receive modules used for telemetry control
LSB
Lower Side Band (see SSB)
back to index
MF
Medium Frequency (300kHz-3MHz)
MHz
Megahertz - 1,000,000 cycles per second
MSK
Minimum Shift Keying. Another term for FFSK
MOBILE
In the general sense, describes a system in which a radio communications link is maintained whilst on the move e.g. a user can continue a conversation in a moving vehicle train. Applied to cellular subscriber equipment refers to permanently vehicle-mounted equipment as distinct from hand-portables
MODEM
A contraction of the term "modulation-demodulator". A modem converts the serial digital data from a transmitting terminal into a form suitable for transmission over the analogue telephone channel. A second unit reconverts this signal to serial digital data for acceptance by the receiving terminal
MODULATION
The process of impressing information on a carrier usually by varying either its amplitude or frequency
MoU
Memorandum of Understanding, a document that details agreements between parties with a common interest
MULTIPLEXING
In communication systems, the function of transporting more than one stream of data over a single circuit (real or virtual) apparently simultaneously. Multiplexing can be either in the frequency domain (FDM) or the time domain (TDM)
MUTING
The process by which the audio circuits of a receiver are turned off in the absence of a carrier on the appropriate frequency. Used in conjunction with CTCSS and Selcal to achieve selective reception by a mobile or group of mobiles
back to index
NGN
Non Geographic Numbers
NMT
Nordic Mobile Telephone - cellular system standard evolved by the Nordic countries
OEM
Original Equipment Manufacturer
OFCOM
Office of Communications
PABX
Private Automatic Branch Exchange
PAMR
Public Access Mobile Radio - A PMR Two-Way Radio type of service provided by a third-party Network Operator
PBX
Private Branch Exchange
PBR
Private Business Radio (see PMR)
PCM
Pulse Code Modulation. An encoding technique for digitising analogue voice signals
PCN
Personal Communications Network. Used generically to describe a mobile communications system for use with a mass market low cost hand-portable
PCS
Personal Communications System. A universal mobile personal telecommunications system usually involving a base station, dispatch centre and vehicle-mounted mobile transceivers
PDN
Public Data Network
PMR
Professional / Private / Personal Mobile Radio - Two Way Radio - Generally recognised as the term covering communications other than mobile telephones
POCSAG
Post Office Code Standardisation Advisory Group. Industry standard coding scheme for addressing pagers
PSTN
Public Switched Telephone Network
PTNC
Public Telecommunications Network Operator
PTT
Press To Talk - often used to describe the transmit button on a PMR two-way radio
back to index
Q
no entries
RA
Radiocommunications Agency - the spectrum regulator prior to OFCOM
RF
Radio Frequency. Carrier frequencies used for radio communications
RFID
Radio Frequency IDentification - tagging and tracking items
RIS
Radio Investigation Service - part of Ofcom dealing with keeping the spectrum 'clean' and free from interference
RLAN
Radio Local Area Network
RoHS
Restriction of the Use of Certain Hazardous Substances
RPC1
Radiopaging Code No. 1. The CCIR equivalent of POCSAG
RTPI
Real Time Passenger Information
RTTE
Radio and Telecommunication Terminal Equipment - A European Directive enabling manufacturers to 'self-certify' their product for technical compliance and to place them on the market
RX
Receiver
Acronyms S - Z
Scroll down to find the acronym or term you want defined (or use Control-F to search the page)
back to index
SELCALL
Selective Calling. In PMR systems, a method of sending control information by means a sequence of, usually, five tones
SIDEBANDS
The radiation of frequencies above and below the carrier frequency which result from modulation of a carrier
SHF
Super High Frequency - above 30 GHz
SIM
Subscriber Identity Module
SIMPLEX
A one-way communications channel
SLA
Service Level Agreement
SMO
Spectrum Management Organisation
SPC
Stored Program Control. Generally the application of computer techniques to the control of private or public telephone exchanges
SSB
Single Side Band. A modulation method used mainly on HF (Short Wave)
STS
Sequential Tone Signalling
STH
Short Term Hire
back to index
TACS
Total Access Communication system - analogue cellular system standard used in the UK and derived from AMPS
TCBS
Trunked Common Base Station
TCVR
Transceiver - a combined TX and RX
TETRA
TErrestrial Trunked RAdio - originally a European digital trunked radio ETSI standard
TDD
Time Division Duplex. A technique for achieving full duplex on a half duplex channel by using time
division multiplexing
TDMA
Time Division Multiple Access
TOKEN BUS
A LAN technology specified in ISO 8802/4 and IEEE 802/4
TOKEN RING
A LAN technology specified in ISO 8802/5 and IEEE 802/5 primarily supported by IBM. Employs a system of token passing for media access
TX
Transmitter
back to index
UHF
Ultra-High Frequency. Used to describe radio signals in the 300 MHz to 3GHz frequency band
UMTS
Universal Mobile Telecommunications Service. A pan-European research project aimed at unifying all the existing mobile networks into a single standardised environment
USB
Universal Serial Bus or alternatively Upper Side Band (see SSB)
VHF
Very High Frequency. Used to describe radio signals in the 30MHz to 300MHz frequency band
VoIP
Voice over Internet Protocol
WAN
Wide Area Network. To be distinguished from the LAN, a WAN interconnects geographically remote sites
WAP
Wireless Access Protocol
WARC
World Administrative Radio Conference (of the ITU)
WEEE
Waste Electrical and Electronic Equipment
WIRELESS
A generalised term used to describe a non-wired communication link
WLAN
Wireless Local Area Network
WLR
Wholesale Line Rental
ZVEI
Zentralverband Elektrotechnik-(Electronic Manufacturing Industry Association of Germany) Standards body which has specified one of the coding schemes used in Selcall
Back to index