GEC
TEL/10T/ATT

GEC 1000 Type Automatic table telephone

Introduced in 1956.

Used on private telephone systems.

Note that vents are fitted on the case sides, close to the handset. These can also be used to pick up the phone by using a thumb and finger.

These phone could be supplied tropicalised. Easily identified by mesh that covered the sound holes in the base to stop insects entering the telephone.

The base plate can easily be removed by unscrewing, but not removing, the four corner screws in the base.

Dating these telephones can be difficult, but they were introduced in 1956 and sometimes on the capacitors, inside the telephone (metal cylindrical items), there may be a date.

They also could be supplied with coloured casings, but in all instances the handset was coloured black. GEC attributed this as cost effective as only one colour had to be stocked for maintenance purposes.

How to convert this telephone to the UK PST System

There are two sets of terminals. 'A' terminals are on the left and 'B' terminals to the right.
Using a standard UK line cord:-

Remove and discard the old line cord.
Remove the link B4 - B7.
Feed the new line cord through the casing entry hole and tie it or knot it to prevent it being pulled out.
Install a 3.3k resistor between A6 & A7.
Connect the White wire of new line cord to terminal A6.
Connect the Red wire of new line cord to terminal B7.
Green wire of new line cord - spare - insulate.
Connect the Blue wire of the new line cord to terminal A5.
Check transmission and replace transmitter if bad and always fit a Rectifier element across the receiver on terminals B1 & B3. Click here for more information.

If the phone is noisy (frying bacon), blown in the microphone and see if the noise changes. It probably will meaning the transmitter requires replacing. If you short out terminals B2 and B5 and the noise goes then that also proves the issue to the Transmitter.