My home came with a c.2007 On-Q Legrand Inquire 1000 intercom system. All stations only issue a gravely hiss. The Talk and Door buttons do not work. Mute works. Volume adjust works.
All units use Cat 5 cabling routed to a panel in a closet which is powered thru a power supply.
I am thinking I could install a Ring Doorbell Elite (or equivalent) using its PoE capabilities but it is quite expensive (after all is said and done ~ $500 per door).
I then wondered if I could just use the Cat 5 cable as a power cord (divide the wires into 3 sets for hot, common and ground) and connect it to a new transformer in the closet cabinet, then plug that into a wall socket. If so, that would cost me ~ $100 for the door bell, chime, and transformer.
I am at the idea/design stage so all suggestions that can utilize the Cat 5 cable to get me a door bell without having to pull new electrical cable or necessarily use WiFi would be appreciated.