Thanks @Juergen !
Today I came to test it finally with my 4630/02.
It does work much better than before. So it recognizes the ring (which did not work before). I followed the wiring instruction and made sure it’s correct twice.
Anyhow, it can not open the lock at the gate (the button on my ritto works though). Also, I tried the 2-persons variant to configure it but it didn’t help either.
What else could I do to to configure it?
Btw, others in my compound use newer phones at the same bus. (If that makes any difference).
Any help is greatly appreciated, I believe it’s only the last bit of modification.