I don't have my CID list in front of me. But I think it sends a 602 test signal. Basically, picks up the line, calls the CS, handshakes, gives the test signal, then hangs up. If you get no warning of a fault then all is okay. I wouldn't worry about testing the panel until you get a working phone line, I've never had a panel that has failed to interrupt the phone line and deliver a signal. If a working phone line is difficult to obtain then you could test it with a cellular backup set as the primary.