Hi Georg,
My Platea Plus monitor 11758802 is wired similarly to Ricardo’s. Based on Golmar documentation, this system is referred to as a 3-wire coax - positive (+), audio communication (A) and digital communication (D) with the coaxial cable for video.
Could you confirm that the Golmar Plus tests for Opener has only been based on the video door entry system without coaxial cable - 4 wires with twisted pair system? This would really save a lot of people investing in a Nuki setup only to find that although the monitor is listed as compatible that they also need to consider the intercom wiring system of their building.