Identification marking used on the base of GPO telephones
GPO telephones usually had identifying marking on their base. This normally consisted of a 3 digit number indicating the type of telephone. This was sometimes followed by a suffix code used to indicate a feature of the phone. Next there were one, two or three letters to indicate the manufacturer. Then came two numbers which were the last two digits of the year. Finally came a number and sometimes a letter to show a change in production.
The example on the left gives the following information about the telephone:
- 706 type No: 706
- L dial marked with letters
- PLA made by Plessey
- 64 made in 1964
- 2A production run 2A
Suffix codes
| CB | Central Battery (no dial) |
| F | All-figure dial or dial surround |
| L | Letters and numbers on dial or dial surround |
| LB | Local Battery (dial fitted) |
| R | Recall button fitted |
Manufacturer’s codes
| AEG | GEC Telecommunications, Glenross, Scotland |
| AEK | GEC-AEI Telecommunications, Kirkaldy, Scotland |
| C | General Electric Company (GEC), Coventry |
| CWL | Pye Telecommunications, Cambridge |
| DAE | A. P. Besson Ltd., Hove, Sussex |
| DFM | Denis Ferranti Meters Ltd. |
| E | Ericsson |
| EET | Plessey, Beeston, Nottinghamshire (formerly Ericsson) |
| EEX | Plessey, Sunderland (formerly Ericsson) |
| FB | GPO Factory, Birmingham |
| FBR | GPO Factory, Birmingham (Refurbished) |
| FH | GPO Factory, Holloway, London |
| FHA | GPO Factory, Holloway, London (Assembly) |
| FHB | GPO Factory, Holloway, London (Construction) |
| FHR | GPO Factory, Holloway, London (Refurbished) |
| FNR | GPO Factory, Edinburgh (Refurbished) |
| FRA | Ferranti Ltd. |
| FH | GPO Factory, Holloway, London |
| FW | GPO Factory, Cwmcarn, Wales |
| FWG | STC Consumer Electronics, Cwmcarn, Wales |
| FWR | GPO Factory, Cwmcarn, Wales (Refurbished) |
| G | General Elecric Company (GEC) |
| GEC | GEC Telephones, Coventry |
| GEN | GEC-AEI Telecommunications, Newton Aycliffe, County Durham |
| GNA | Pye (laterally TMC), Aidre |
| H | Automatic Telephone & Electric Company |
| HAA | Plessey Strowger Works, Liverpool |
| I | Ibex Telephones, Harrow |
| IBX | Ibex Telephones, Harrow |
| PEH | Pye, Hastings |
| PER | Plessey, Romford, Essex |
| PL | Plessey |
| PLA | Plessey |
| PLS | Plessey, Swindon |
| PLX | Plessey, Newport, Gwent |
| PX | Phoenix Telephones, Hendon, London |
| PXA | Phoenix Telephones, Hendon, London |
| S | Siemens Brothers (laterally AEI) |
| SER | Siemens, West Hartlepool |
| SLW | Plessey, Wigan |
| SPK | Plessey, Speke, Liverpool |
| STC | Standard Telephone Company (STC), New Southgate, London |
| STM | Standard Telephone Company (STC), Belfast, Northern Ireland |
| TCH | Standard Telephone Company (STC), Larne, Northern Ireland |
| TE | Telephone Manufacturing Company (TMC) |
| TEA | Telephone Manufacturing Company (TMC), West Dulwich |
| TES | Telephone Manufacturing Company (TMC), St. Mary Cray |
| TGR | Thorn Ericsson, Rochester |
| TGW | Thorn Ericsson, Scunthorpe |
| TMA | Telephone Manufacturing Company (TMC), Airdrie |
| TSD | Telephone Supplies Ltd – Aycliff, Co. Durham |
| TTL | Telephone Manufacturing Company (TMC), Livingston, Scotland |
| W | Western Electric (laterally STC) |
A more exhaustive list of codes manufacturer’s codes is available on Bob Freshwater’s site