Nuki Opener with SKS GF40/S


I was trying to connect the Nuki Opener with my GF40/S but was not able to get it to work.
I know what the cables are for but was not able to find any docs about the GF40.

White - Bell Front Door
Blue - Bell Apartment Door
Red - Opener
Black - Seems to be Speaker/Mic

Does anyone have experience with this or have an idea how to get it to work?

I was able to make it work, but ring suppression doesn’t work.

And I was wrong regarding the wires red and black.

Red is mass
and Black is for opening and also mic and speaker somehow.

My wiring:

Violet - 2
Green - 4
Blue - 1

I do not use the SPK and MIC wires.