Abstract: A security terminal for use with a two-way interactive cable system. The security terminal develops alarm and supervisory signals, and controls their transmission over the cable when polled by a central station. The terminal discriminates between four different types of alarm condition (burglary, fire, medical and general emergency), and transmits respective coded signals over the cable, or over a switched telephone network if cable transmission is not successful. To further insure that alarm signals are properly transmitted in the event of a cable outage, the terminal responds to a cable-sent test command from the central station by causing the dialer to dial the central station over the switched telephone network; in this way, the dialer mechanism can be tested periodically to insure that it will be operative if needed.