Detailed Security System & Fire Alarm Definitions
Quick Reference Security Systems Definitions
Fire Alarms & Accessories Definitions
Door Access Control Definitions
Closed Circuit Television CCTV Definitions
Phone Systems Definitions

Addressable Device - A component of a fire alarm system that has a specific identification and location. These devices allow the user to check the individual status of a device and control many other functions.

Alarm Signal - A signal that is initiated by one of the devices on the system due to a fire emergency.

Analog Initiating Device - A device that indicated different degrees of conditions, as compared to a conventional device that only indicated a on or off condition.

Annunciator - A unit containing information pertaining to the condition of system circuits and devices.

Audible Signal - The sound produced by a notification appliance such as a bell or horn when one of the initiating devices goes into alarm.

Authority Having Jurisdiction (AHJ) - The local organization that is responsible for approving a fire alarm system installation and plans.

Class "A" Circuit - The wiring of initiating devices and notification appliances so that a single open or ground on the circuit does not cause the loss of the alarm system's function.

Class "B" Circuit - The wiring of initiating devices and notification circuits so that a single open or ground on the circuit does cause the loss of the alarm system's function.

Digital Alarm Communicator Receiver (DACR) - A component that receives signals from a communication transmitter (DACT). These signals contain information pertaining to the condition of the alarm system.

Digital Alarm Transmitter (DACT) - A component that transmits signals to a communication receiver (DACR). These signals contain information pertaining to the condition of the alarm system.

Fire Alarm Control Panel - A component that receives inputs form initiating devices and sends outputs to notification appliances. This unit also supplies partial or all power to system components. This unit may incorporate a DACT to transmit signals to a DACR.

Initiating Device - A component such as a smoke detector or pull station that transmits an alarm signal to a control panel.

Initiating Device Circuit - A circuit to which initiating devices are connected.

Notification Appliance - A component such as a horn or strobe that provides audible and/or visible alarm outputs.

Notification Appliance Circuit - A circuit to which notification appliances are connected.

Spot Type Detector - A component that detects only in a particular location.

Supervisory Signal - A signal that indicates the need for maintenance pertaining to certain components in the system.

Trouble Signal - A signal that indicates a fault in a circuit or system component.

Zone - A specific area within a protected premise that defines the type of alarm and/or location.