| A&B | A&B type coin collecting Box |
| Adj | Adjustable |
| Aka | also known as |
| Alt | Alternative |
| AR | Alternative recall i.e. Timed break recall |
| Auto | Automatic |
| BLF | Busy lamp field |
| BPO | British Post Office |
| BS | Bellset |
| BT | BRITISH TELECOM |
| BTRL | British Telecom Research Laboratories |
| C/O | Cut off |
| CB | Central Battery (System) |
| CBS | Central Battery Signalling |
| CCB | Coin collecting box |
| CCT | Circuit |
| CCU | Common control unit |
| CO | CALL OFFICE |
| CPU | Central processor unit |
| CSA | CALLED SUB ANSWERED |
| DDI | Direct Dialling In |
| DEL | Direct Exchange Line (a normal subscribers line) |
| Dept | Department |
| DIS | Disconnection |
| DISA | Direct Inward System Access |
| DP | distribution point |
| DS | Dual signalling |
| DSS | Direct station select |
| DT | Dial tone |
| DTMF | Dual Tone Multi Frequency |
| Dual sig | Dual Signalling - i.e. both loop disconnect or DTMF |
| ER | Earth Recall |
| Exch | Exchange/s |
| Extn | Extension |
| FNF | Fault not found |
| FUW | For use with |
| GPO | GENERAL POST OFFICE |
| Inst | Instrument |
| LB | Local Battery |
| LCD | Liquid Crystal Display |
| LD | loop dial |
| LJU | Line Jack Unit |
| LNR | Last Number Redial |
| MDF | Main distribution frame |
| MF | Multi frequency |
| Mag | Magneto System |
| Manu | Manufacturer |
| Mem | Memory |
| N.T.C. | National Telephone Company |
| No. | Number |
| Nos. | Numbers |
| NU | Number Unobtainable |
| OH | OVERHEAD |
| OHD | On Hook Dialling |
| PABX | Private branch exchange system |
| PB | Push Button |
| PBX | Private branch exchange |
| PET | Permanent Engaged Tone |
| PG | permanent glow |
| PI | Postal Instruction |
| PMBX | Private manual exchange system |
| PO | POST OFFICE |
| POT | plain old telephone |
| pps | Pulses Per Second |
| PST | Plug and socket Telephone |
| RR | Register Recall (Timed Break) |
| RTNR | Ring tone no reply |
| RWT | Right when tested |
| Recall | Could be either Earth Loop or Timed Break or both |
| S/S | Shared Service |
| SARCRAM | |
| SC | Self Contained (Loop disconnect keypad) |
| SC | Short circuit |
| SNR | Saved Number Redial (stores last number dialled for redial) |
| Sim | Similar to |
| T | Tone |
| TAMS | Telephone answering machines |
| TB | Time Break |
| TBR | Time break recall |
| TELE | Telephone |
| TI | Telecom Instruction |
| Tele | Telephone |
| UAX | Unit Automatic Exchange |
| UG | UNDERGROUND |
| BACK | Home page | BT/GPO Telephones | A - Z Index | Glossary of Telecom Terminology | Quick Find | All Telephone Systems |
FM