Integrating a dumb doorbell: legrand Selective Call Intercom

Is there a way to wire up a dumb doorbell (in this case, a legrand Selective Call Intercom door unit), so that I can make a rule that triggers the entryway lights when the doorbell is activated (after sunset)? I like this intercom setup for our needs, but it is a bummer it appears to be completely 'not smart'.

Thank you!

I'm not familiar with the Legrand system, but this thread might give you some ideas.

Thanks. I guess the fundamental question is: is there some sensor device that I can put inline on the cat5e line, between the door unit and where it plugs into the intercom distribution module. (That will not interfere with the function of the door unit.)

you could use a zen16 (it might be overkill as it gives 3 relays), but connect the doorbell to the input switch, and the output goes to your doorbell chime

Thank you, @dadarkgtprince. Would something like that potentially interfere with the door unit voice function, or should it continue to operate normally? I could not tell if the zen16 unit had ports for cat5e.

Probably not. Im going to assume the doorbell itself is simply a 2 wire contact button going to a circuit board on the intercom? Either way you just need to go through the relay 1st which will trigger what ever you want.

@rlithgow1, this door unit connects to the intercom system with a cat5e, and allows the visitor to speak with a person in the house who is at an intercom unit.

You will have to find which 2 wires within that cable connect to the chime portion of things (so it doesn't interfere with the intercom) and branch them off to the relay then back into the cable


This older post might give you some ideas. Realize it’s a different system but the OP discusses many things he tried.


Thank you. My ignorance is showing, and I appreciate this clue. I will try asking the manufacturer to see if they can tell me which two wires to target, before I mess around trying to figure it out!

@caseyb just googled selective call and found Legrands website and installation instructions. Not sure exactly which model but this one talks about dry contact terminals on the main unit to “ring a customers 3rd party door chime”

Check yours to see if you have it and if so solution is easy you just need to get a contact sensor with external input terminals like the Ecolink Contact Sensor and you are good!

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Yes! If only I could get another wire out to that location. It's all sealed up already, and would require removing siding.

This isn't your outdoor unit... this is your main intercom unit inside the house. I'd pull it off the wall
and look.


Hm. I will, thank you.