Fire Alarm Control Units, Supervising Stations, and Signal Transmission
FACU and supervising stations
A fire alarm control unit receives initiating signals, processes them, and controls notification and interface outputs. It must clearly annunciate alarm, supervisory, and trouble conditions and must monitor its own power supplies and circuits. Supervising station types include central station, proprietary, and remote supervising station. A central station is a listed, staffed facility that monitors many accounts and retransmits signals to responders. A proprietary station is owned by the protected property and staffed for its own systems. A remote supervising station receives signals at another location, often a fire department.
Signal transmission
Transmission methods include digital alarm communicator transmitters over telephone lines, internet protocol, cellular, and radio. The signal path must be supervised so a failure is annunciated at the protected premises or supervising station. Account codes and test signals must be correct. Alarm signals generally receive priority over trouble and supervisory signals. End-to-end testing verifies that the signal reaches the supervising station, not just that the dialer powers up.
Worked example. A manufacturer's campus has 24-hour security staff and wants to monitor its own buildings. A listed proprietary supervising station may be appropriate because the property owns and staffs the receiving point. A stand-alone retail building without on-site staff is better served by a central station, which can retransmit to the fire department. In both cases, the transmission path must be supervised and tested end-to-end.
Traps that cost marks
Do not treat a telephone trouble as an alarm. Do not assume an internet path is supervised just because it works. Do not omit account codes or test signals. Do not confuse proprietary with central station. Do not accept a panel-only test as proof that the supervising station received the signal.