This is lovely example of a GPO dial Trimphone. A pulse to tone unit has been fitted. It has been totally stripped down and re built after each part has been cleaned and polished. It has been fitted with an electronic microphone which is essential on a Trimphone as the small carbon granule mics were not very good at all and crackle hand hiss. This has been set up on a special line simulator and then tested on our own BT land line to make sure it is working perfectly to both dial out and receive. I can make a dial label with your information at no extra charge.