fire alarm control panel monitor inputs and control outputs through various types of circuits.the inputs are from initiating devices. The most common output of a building fire alarm system is the activation of occupant notification appliances. The fire alarm control unit might also control relays or provide data to other systems in order to control emergency functions such as elevator recall or the unlocking of doors.
Smaller systems or conventional zoned systems might have simple displays with LEDs to indicate which zone is in alarm or supervisory mode.
Addressable systems and many newer zoned systems use text displays to indicate the status of the system. Larger and more complex systems may have multiple operator interface panels and may have additional controls for making voice announcements and for controlling building features such as fans, elevators. And doors.