I have a Urmet Signo 1740/40 intercom device in my apartment, and I've been brooding on a way to replicate (some of) its functionality from a different device (such as a Raspberry Pi) so that I can control it from e.g. a web interface or mobile app. However, I could use some pointers to get started with the electronic aspects of it.
After opening up the device, I found the following PCB. The thing that immediately draws attention is the 22-pin connector that connects the front side of the device to the PCB (bottom-left just below the dip switches). Given that the front panel contains the buttons as well as audio/video interfaces, it would appear that everything I would want flows via this connection. See the photos below.
My main question is: what would be the best way to approach reading the signal from an external device? I thought about wiring each of the pins to GPIO input pins of a Pi to try and reading out the value while using different functionality of the device, but I feel like I know way too little about this thing to know if that will cause damage. I would like to learn how to do this properly, though.
Does anyone recognise this type of connector? Is this likely to be a standard, or is it something proprietary they might have cooked up themselves? What equipment would you suggest when trying to do this?
I have not really been able to find any documents on the technical specifications of this device other than install guides.. Are these things commonly available? What is a good starting point?