Automate an old intercom

Hello, I have a Videx 901 video intercom installed in my building, that I would love to automate.

I’ve tried to automate it using Ring Intercom, and it worked, at least the part where Ring recognized that someone rings the door, but supposedly it should also be able to open the door via the app, but it fails to open the door. I contacted Ring and they told me that my Intercom isn’t compatible with Ring Intercom. The goal was to use Ring Intercom and then connect it using Ring-MQTT to Home Assistant to be able to automate my building door in order to let deliveries and visits in.

Nevertheless, I would be happy if I could do it using Tasmota or ESPHome to automate my Intercom, I have the schematics but I lack the electronics knowledge to fully understand which cable I need to connect to. I know which cables are used to receive the input when someone rings the door and even which ones are used to talk to and hear the person outside, but the cable that is supposed to open the door doesn’t work (at least with Ring Intercom), it’s supposed to be cable 2 (accordingly to intercom manual, vide picture below) but seems like it doesn’t unlock the door.

The manual says that I need to pick up the handset and turn on the video to open the door when I press the button on the intercom, but that’s not true, once someone rings the door, the video turns on automatically and I don’t need to pick up the handset to be able to open the door with the intercom button, so I guess that it should be possible to (connecting to the right cable) dispatch an electric pulse to open the door.

Problem 1
What would be the cable and which charge should be needed to be dispatched in order to open the door?

Problem 2 (bonus)
With Tasmota or ESPHome would I be able to have a way to have two-way communication? If so, what do I need to have and how do I connect that with HA?

Problem 3 (extra bonus)
Would I be able to see the camera of my intercom in HA somehow? The intercom uses a Coaxial signal to stream the video feed from the outside intercom. Is there a way to convert that into digital and then stream it to HA?

Is there someone that knows or is able to help me achieve this? I have the technical manual of the intercom in case more information is needed.

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I have a similar problem but I haven’t tried Ring as it says it is not compatible. My system is 3-wire + coaxial. similar to yours?

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I recently managed to make it work.
You have to connect the cables this way:

If you get continuous notifications that someone is at your door, change

I believe that it will work

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Sorry for the late response, I’ll give it a try