| AC |
Alternating current |
| ACD |
Automatic Call Distribution |
| AM |
(British) Air Ministry |
| AP |
Admiralty Pattern (precedes type number, on all manner of
British Navy equipment) |
| APNSS |
Analogue Private Network Signalling System |
| ASTIC |
Anti-sidetone induction coil (circuit) |
| AUTO |
Automatic, fitted with a dial |
| AVO |
A particular UK make of multimeter (AVO stands for amps,
volts, ohms) but often applied to any multimeter |
| ATE |
Automatic telephone exchange or the manufacturer AT&E
Ltd |
| AWG |
American Wire Gauge. Almost the same as the British SWG |
| BABT |
British Approval Board for Telecommunications |
| BDF |
Building Distribution Frame |
| BSP |
Bell System Practice (US equivalent of an EI) |
| BT |
Block Terminal |
| BTR |
British Telecom Requirement |
| B/W |
Both way |
| CAI |
Common Air Interface |
| CAS |
Channel Associated Signalling |
| CB |
Central Battery (not fitted with a dial) |
| CBS |
Central battery signalling |
| CCITT |
Consultative Committee International Telegraph and
Telephone |
| CCS |
Call Connect System |
| CNA |
Change of Number Announcement |
| CNI |
Change of Number Interception |
| COS |
Class of Service |
| CPE |
Customer premises equipment |
| CRA |
Call Routing Apparatus |
| CT |
Cordless telephone |
| CUG |
Closed User Group |
| Cx |
Continental (BPO expression) |
| DAS |
Directory Access System |
| DC |
Direct current. |
| DDD |
Direct Distance Dialling (the American expression for STD) |
| DDI |
Direct Dialling In |
| DECT |
Digital European Cordless Telephone |
| DEL |
Direct exchange line (i.e. not an extension or a private
wire) |
| DES |
Direct Extension Select |
| DIS |
Disconnected, i.e. open circuit |
| DISA |
Direct Inward System Access |
| DND |
Do Not Disturb |
| DOVE |
Data Over Voice Equipment |
| DP |
Distribution Point |
| DPNSS |
Digital Private Network Signalling System |
| DS |
Dual signalling (loop-disconnect and DTMF) |
| DTE |
Data terminal Equipment |
| DTMF |
Dual tone multi frequency |
| AEROM |
Electrically alterable read only memory |
| EI |
Engineering Instruction (BPO, APO and NZPO expression) |
| ELR |
Earth Leg Recall |
| ETD |
Extension Trunk Dialling (direct extension-to-extension
national dialling on British Railways) |
| ETSI |
European Telecommunications Standards Institute |
| FDDI |
Fibre Distributed Data Interface |
| FDM |
Frequency Division Multiplexing |
| FDP |
Floor Distribution Point |
| FNF |
Fault Not Found |
| IBTE |
Institution of British Telecommunications Engineers
(former IPOEE). |
| IC |
Incoming or Integrated Circuit |
| ICD |
Internal Cable Distribution |
| IDA |
Integrated Digital Access |
| IDC |
Insulation Displacement Connection |
| IDD |
International Direct Dialling |
| IDN |
Integrated Digital Network |
| IEE |
Institute of Electrical Engineers |
| IEEE |
Institute of Electrical and Electronic Engineers (USA) |
| I/F |
Interface |
| IPOEE |
Institution of Post Office Electrical Engineers (now IBTE). |
| ISD |
International Subscriber Dialling, later retitled IDD |
| ISDN |
Integrated Services Digital Network |
| ISO |
International Standards Organisation |
| Ix |
International (BPO expression) |
| KS |
Kearny specification, named after the Western Electric
plant in Kearny, New Jersey. KS numbers were applied to items made by
Western Electric for the Bell System and to things made for Bell by
other companies |
| KTS |
Key Telephone System |
| LAN |
Local Area Network |
| LCD |
Liquid Crystal Display |
| LCR |
Least Cost Routing |
| LED |
Light Emitting Diode |
| LD |
Loop Disconnect |
| LJU |
Line Jack Unit |
| LNR |
Last number redial. |
| LST |
Loudspeaking telephone. |
| MAT |
Maintenance Acceptance Test |
| MCL |
Mercury Communications Ltd |
| MD |
Manufacturer discontinued (Bell System expression, USA) |
| MDF |
Main Distribution Frame |
| MF |
Multi-frequency (often refers to signalling) |
| M, mic |
Microphone |
| MGS |
Miscellaneous government surplus |
| mil. spec. |
Military specification (high quality standard) |
| MMI |
Man, Machine interface |
| MOD |
Model, modification, modulation |
| MOH |
Music on Hold |
| MTBF |
Mean Time Between Failures |
| N |
Number |
| N/A |
Information not available |
| NCOP |
Network Code of Practice |
| NCP |
Network Connection Point |
| NDS |
Network Distribution System |
| NET |
Norme Europeenne de Telecommunications |
| NSN |
(on components) NATO stock number |
| NTP |
Network Terminating Point |
| NTTA |
Network Termination and Testing Apparatus |
| O/C |
Open circuit |
| PABX |
Private automatic branch exchange (with connection to the
PSTN) |
| PAX |
Private automatic exchange (not connected to public
networks) |
| PCB |
Printed circuit board or Poly Chlorinated Biphenol, a
hazardous substance |
| PF |
Picofarad |
| PH |
Publicity
handout (BPO expression) |
| PMG |
Postmaster
General (Australia) |
| PO |
Post Office |
| POEEJ |
Journal of the IPOEE |
| PPS |
Pulses per second |
| PS |
Power
supply |
| PST |
Plug-and-socket
terminated |
| PSTN |
Public switched telephone network |
| PSU |
Power
supply unit |
| PTO |
Public
Telecoms Operator |
| PTT |
Press-to-talk
(method of switching from receive to transmit) or Post, Telegraph and
Telephone administration |
| PU |
Power
unit or (gramophone) pick-up |
| PW |
Private Wire |
| PWB |
Printed wiring board (alternative expression for PCB) |
| pwr sup |
Power supply |
| PXML |
Private Exchange Master List |
| Q |
Abbreviation for capacitor or transistor on circuit
diagram, alternatively the figure of merit for a tuned circuit |
| R, RCVR or RX |
Receiver |
| RAM |
Read access memory |
| ROM |
Read only memory |
| RWT |
Right When Tested |
| S/CRTNR or short |
Short circuit |
| SC |
Self-contained, i.e. a loop-disconnect push button
telephone not requiring an external power supply |
| s.c.c. |
Silk-covered cotton (wire) |
| SCDC |
Single Commutation Direct Current |
| SCRA |
Small Call Routing Apparatus |
| SA |
Subscribers' Apparatus (also the prefix for a BPO series
of drawings) |
| SPC |
Stored Programme Control |
| SR |
Special Range (prefix to BT title numbers) |
| STD |
Subscriber Trunk Dialling |
| STP |
Shielded Twisted Pair |
| SWG |
Standard Wire Gauge |
| T |
Telephone or tropicalised |
| TBR |
Time Break Recall |
| TDM |
Time Division Multiplex |
| TEMA |
Telecommunications Equipment Manufacturers Association |
| Tg |
Telegraph (BPO expression) |
| TI |
Technical Instruction (BPO expression) |
| TIA |
Telecommunications Industry Association |
| TJF |
Test Jack Frame |
| TMA |
Telephone Managers Association |
| TOS |
Temporary out of Service |
| Tp |
Telephone (BPO expression) |
| TR |
Transmit-receive |
| TUA |
Telecommunications Users Association |
| TX, TXMTR |
Transmitter (often used as a synonym for microphone) |
| TXD |
Telephone Exchange Digital |
| TXE |
Telephone Exchange Electronic |
| TXK |
Telephone Exchange Crossbar |
| TXS |
Telephone Exchange Strowger |
| UAX |
Unit automatic exchange |
| UPS |
Uninterrupted Power Supply |
| U/S |
Useless, unserviceable |
| UTP |
Unshielded Twisted Pair |
| VDU |
Visual Display Unit |
| VOM |
Volt-ohm meter, multimeter |
| VPN |
Virtual Private Network |
| VTVM |
Vacuum tube voltmeter, i.e. VVM |
| VVM |
Valve voltmeter, what people used before high-impedance
multimeters became widely available |
| x |
General
cypher used to shorten words |
| xcvr |
Receiver |
| xfmr |
Transformer |
| xistor, xstr |
Transistor |
| xmit |
Transmit |
| xmtr |
Transmitter |
| xtal |
Crystal |
| WAN |
Wide Area Network |