Wiring a 4 wire intercom station to a 3 wire.

markcars · Mar 2, 2022

I have an old 3 wire intercom station which I removed, and purchased a new one. Happens that the new one has 4 wires.
Is it possible to connect my 4-wire intercom station to the 3 wires from the wall?

Also if anyone has the internal switch schematic, that would help diagnosing this if its possible.

catdog1121 · Mar 2, 2022

You would have to look at the instructions.. I don't really do intercoms but I would presume its like anything else it would depend what it used the other wire for, often there are instructions for wiring different ways for different systems, but it could be if it needs the 4th wire and you don't have it then no it wont work..

pirate · Mar 2, 2022

Sometimes. looking at the actual wiring inside a handset, there are commoning links, so it may be that you can connet 3 wires to 4 or 4 wires to 3. It's a tricky question, but one I have had to look at recently on a couple of occasions.
This website has pics of many handsets and their wiring diagrams, so it may assist you. Certainly helped me sourcing replacement handsets for older systems.