Hello to the community,
I moved in a building that is equipped with a very old intercom system. It was built by the company EUPHONE, which no longer exists and disappeared before the Internet was mainstream, so no information on the web.
I have replicated the electronic component of the intercom in a Falstad file (Circuit Simulator Applet). the file is here: https://is.gd/m0ptNK .There are 10 connectors on the intercom, with six wires coming from the street and 4 used to connect to the internal speaker and microphone. What I don’t know is how the six wires coming from the wall (noted A, B, C, D, E and F) are connected on the main console at the entrance of the building. I have made scenarios, but I am not skilled enough in electronics to solve it entirely.
The cinematic is this: I have a Talk button and an Open button on my intercom. While at rest, these two buttons have no effect. When someone rings, I can hear the street. I can then push the Talk button to engage in a conversation, and then press the open button. After a few seconds/minutes, it all becomes at rest again.
I am guessing that pressing the Open buttons shorts the wire F and C, which are related to Mic and Speaker. For the short to be useful, the wire C is powered when someone rings. And I’m guessing the Ring signal comes on wire B, closing the left relay and sending current through the speaker via wire D.
Can someone put me in the right direction? Thanks!!!