How to find correct wires for analog intercom phone

[symbianas]

Hi, I have moved to flat which has intercom system "Miwi-Urmet 1131", but phone is missing, so I want to connect a new one, but need to know correct wiring.
It seems to have 5 wires and be analog intercom system.

Wires:
White - maybe door lock or ground? when this wire is connected to green door lock makes some noise but does not unlock...
Green - maybe ground?
Red - maybe speaker but does not seem to work...
Brown - seems to be microphone wire? when connected with green as ground other person hears me near the house entry. When white is connected as ground sound is bearable too but very distorted.
Gray - Ringing wire? phone rings then this wire connected to RING and green or white is connected to

When measuring with multi-miter white seems to be the ground 0V green 8V brown 14V. But microphone and ringing works then green is connected to the ground.
The problem is that door lock and sound in flat is not hearable at all. So for some reason these functions do not work.

Any ideas how to make this intercom phone working? Neighbors say that their phones do work, so intercom should be working...

[SeanB]

Best bet is to look at the wiring for one of the neighbours, and connect yours as they are, as wire colour is not really set in the install manual. New unit will have the wires connected to the handset in the right order, so just install yours as they have. Just note that if there are jumper wires in the other phone, you need to install them as well.

https://urmet.com.pl/INSTRUKCJE/1131_INSTRUKCJA.pdf