[Solved] How to find correct wires for analog intercom phone "Miwi-Urmet 1131"

Hi, I have moved to a flat which has an intercom system called "Miwi-Urmet 1131", but the phone is missing, so I want to connect a new one, but I need to know the correct wiring.
It seems to have 5 wires and be an analog intercom system.
I have found a Cyfral Smart 5P analog phone, it should work with Urmet 1131.

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

When measuring with a multimeter, the white wire seems to be the ground (0V), green (8V), brown (14V). But the microphone and ringing work best when green is connected to the ground.
The problem is that the door lock and sound in the flat are not heard at all at the bottom. So for some reason, these functions do not work.

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

Provide a photo of the calling cassette (at the entrance door) from which you are called.

Thanks for the reply, this is the unit at the entry:

Approach one of your neighbors and ask to open the casing and take a photo of the connections inside, because if you do this you will be in trouble for a long time and it is not known whether these actions will damage the entire system in the gate.

No, that's not an option. They won't let me open the phone, I'm a complete stranger to them. I managed to take a picture of their phone if it helps:

Can you tell which wire goes where by checking them with a multimeter?
I have no other choice but to take a risk and find the right cables...

(Translated with Google, original):
No, that's not an option. They won't let me open their phone, I am a complete stranger to them. I was able to get a photo of their phone if that helps.
Is it possible to know what wire goes where by testing them with a multimeter?
I don't have any other options, just to risk it and find the correct wires...

JumalIO wrote:

No, that`s not an option. They won`t let me open the phone, I`m a complete stranger to them. I managed to take a picture of their phone if that helps

The photo doesn`t add anything.
You can also call a service technician for your system.
If you really want to do it yourself, here`s a good guide:
https://www.elektroda.pl/rtvforum/topic3289894.html from point 4.2

>>20921704
You have a connection diagram.
Link
Tel - handset

>>20921786
Hm... I can't find speaker wire, all I hear is static background noise...
What could be wrong?
I have looked in the staircase, there goes 5 wires to outside. I guess I can connect a speaker and listen for outside noise on the neighbor's floor?

I have ordered a technician to come and connect the doorphone, but it costs 54 EUR per hour, which is quite expensive, and I doubt he will connect it fast, as I was unable to find speaker wire...
He should come in 3 days. If you have any ideas that I could try myself, I can still cancel the technician...

It seems it was an issue outside my flat. The wire or a few of them were disconnected or something. All people after the second floor did not have a working door phone, but for some reason they did not complain... So all the flats will cover the repair costs!
After the repairs, I was able to find the speaker wire! I had mixed up the ground and speaker wires at first, but I think I have correctly connected everything now.

Thanks for the help.