Quote "It's because 99.9% of Telguard products are for an alarm system and the elevator phone communicator is probably a modified alarm communicator. So they are not setup to work with the elevator maintenance people. "


You are incorrect on this. An alarm communicator sends pulses to a receiver that will read the pulses, and give a meaning of what the pulse means to the operator working at the "central station".

A elevator phone is a means of two way communication.