Door contact cable laid into the technical room

I unfortunately have no experience with Metzler, but the IP door station from Doorbird offers two ways to securely control the door contact from the inside: either via a relay contact on the indoor station, or via a separate I/O door controller installed in the technical room. For the reasons mentioned above, connecting the door contact directly to a switching relay of the outdoor station is not much of a challenge for tech-savvy burglars.

With Metzler it is also the case that there is a door controller for the technical room, which I also ordered. However, I was not aware of this when the wiring was done here. Now a cable runs from the door to the technical room and a network cable with keystone module (PoE) from the outdoor unit as well. But I cannot control the door controller over that... My current idea is to ask Metzler whether they could exchange the LAN version for a 2-wire IP version. Then the existing LAN cable could possibly be split. Let’s see if they agree to that...

The indoor units have relay outputs. Maybe you can do something with that. Of course, I don't know your floor plan/cable routing.

Theoretically yes. The problem is that except for the network cable, no cable goes to the technical room and I need that for PoE and communication with the indoor stations. Although I still have a power supply in the flush-mounted box, the cable only goes to the next socket. So I can't get the signal from the relay outputs all the way to the technical room... That's why the idea is to convert from PoE to 2-wire.

At Metzler, it is also the case that there is a door controller for the technical room, which I have also ordered. However, I didn’t have that in mind when the wiring was done here. Now there is indeed a line going from the door to the technical room and a network cable with keystone module (PoE) from the outdoor unit as well. But I cannot control the door controller through that...
My current idea is to ask Metzler if they can exchange the LAN version for a 2-wire IP version. Then it might be possible to split the existing LAN cable. Let’s see if they agree to that...

As I said, my problem is that my version with camera, NFC, etc. is only available in the PoE version from Metzler.
I have thought about that as well. Since ONLY the network cable from the outdoor station to the technical room is installed here, the cable would have to be split. That means using the 2-wire version for the signals like bell etc. and the remaining wires as RS485 signal to control the relay in the technical room. The problem I see here is that different signals would be in one cable bundle.
Basically, it is so that the signal goes from the indoor station’s display to the outdoor station, and this switches a potential-free contact. That means some kind of network exchange must take place here.

The question is how tech-savvy you are.

I have a home server running Homeassistant. It reads the data between the indoor and outdoor station. I get all the info there (ringing, commands from the indoor station, etc.) and the camera image. I then use that to control a Nuki door motor. Of course, you can also control a WLAN relay there. And since the indoor station has two "buttons" for unlocking, I use the second one directly for the garage. I also receive NFC info.

You could also, for example, install a Shelly Uni on a contact of the indoor station to read the relay status and switch another relay over IP based on that.

The question is how tech-savvy you are.

I have a home server running Homeassistant. It reads the data between the indoor and outdoor station. I get all the information there (ringing, commands from the indoor station, etc.) and the camera image. Through this, I then control a Nuki door motor. Of course, you can also control a WLAN relay there. And since the indoor station has two "buttons" for unlocking, I simply use the second one for the garage. I also get NFC information.

You could also, for example, install a Shelly Uni on a contact of the indoor station to read the relay status and switch another relay over IP based on that.

I will manage that. Do you get the data via the network interface (if the interface is open, is there a specification for it), or via another interface (RS485, etc.)? I assume the connection between the indoor and outdoor station is not a "simple" UDP or something like that. So, a pure reading should (only) be possible via a switch with a monitor port. Or how should I imagine it?

Thanks, regards