Opener connection with Commax DPV-4MTN intercom


This is a quite old analogue intercom with 4 wires:
1 - Audio
2 - GND
3 - +12V (out)
4 - Video

For opening you have to wake up the intercom with one of the followings:

  • Door bell (Shourtcut between Audio - GND)
  • Press Video Button
  • Pick up the handheld speaker

If the intercom is active, you can initiate the opening which is a shortcut between Audio and +12V

Is there an existing supported device which works similarly, or do somebody have any suggestion for wiring?