Looking for a vintage intercom set - Page 3 - UK Vintage Radio Repair and Restoration Discussion Forum

TonyDuell · 3rd Feb 2017, 5:22 pm

I suggested something similar back in post #26.

The old electrical books (The Boy Electrician, Harpers Electricity Book for Boys, Every Boy his own Mechanic, to name just 3 that are around here) tell you how to make everything from scratch. There is no need to do that. I am sure the carbon transmitter and balanced armature receiver insets from a 700 series telephone could be used. The induction coil could probably be used too. It won't be the right turns ratio, but I woul be very surprised if it didn't work at all.

You could probably re-wire a 700 series telephone into an intercom set. A 706 Mk 1 (hardwired, not PCB) would be the easiest I think. The only thing you couldn't easily use would be the bell, I am sure you could mount a DC bell or buzzer in place of it. There actually was a GPO buzzer designed for this (used on Planphone extensions), they do turn up from time to time.

3rd Feb 2017, 5:22 pm	#41
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	Re: Looking for a vintage intercom set I suggested something similar back in post #26. The old electrical books (The Boy Electrician, Harpers Electricity Book for Boys, Every Boy his own Mechanic, to name just 3 that are around here) tell you how to make everything from scratch. There is no need to do that. I am sure the carbon transmitter and balanced armature receiver insets from a 700 series telephone could be used. The induction coil could probably be used too. It won't be the right turns ratio, but I woul be very surprised if it didn't work at all. You could probably re-wire a 700 series telephone into an intercom set. A 706 Mk 1 (hardwired, not PCB) would be the easiest I think. The only thing you couldn't easily use would be the bell, I am sure you could mount a DC bell or buzzer in place of it. There actually was a GPO buzzer designed for this (used on Planphone extensions), they do turn up from time to time.