atcomsystems.ca/forum Forums General General Telephone & Systems Information Emergency Elevator phone using cellular communication?

A couple of weeks ago a school called me. The elevator phone comes through their IPO on an analog station. The elevator company replaced the phone. The inspector tested it NDT.
I get the call check dialtone from the IPO through. Where did it fail? The elevator company never tied the phone to the line. I gotta retire to a place no phone no Data, just fly fishing.