Use the ERR cable for other purposes

Intercom system? Like on the Enterprise (Kirk). That way you can call everyone for roll call (meal). Or: "Children please go to the bathroom to brush your teeth!" Or: "Parents please go to the children's room for cuddling!"

The proposal at least gives me an idea. I more or less already have the function integrated via the video intercom at 2 locations on the ground floor and upper floor, but not as a hands-free option, rather for a phone call. The monitors are connected via POE and could be easily expanded. I believe a four-wire cable goes to the actuator. One would have to see if POE can be run over it. At the spots next to the door, the monitor for the door intercom on the upper floor would be better placed than near the LAN sockets. One could then also easily add a monitor for the children's room.