APPENDIX-M: GLOSSARY
AC Power Fail. Refers to a condition in which AC power loss is detected by the system.
Alarm Signal. A signal indicating an emergency requiring immediate action, such as an alarm
for fire from a manual station, a waterflow alarm, or an automatic smoke detector.
Signal Silence Inhibit. An option that prevents an operator from silencing the notification
appliances for a preset period of time.
Alarm System. A combination of compatible initiating devices, control panels, and notification
appliances designed and installed to produce an alarm signal in the event of a fire.
Alarm Verification. A preset option that causes the control panel to verify alarms originated by
smoke detectors before indicating an alarm.
Annunciator. A remotely located, electrically powered display, separate from the control
panel, containing LEDs or lamps to indicate the states of the fire alarm system.
Audible Signal. An audible signal is a sound made by one or more audible notification
appliances, such as bells or horns, in response to the operation of an initiating device.
Auto-Silence. The capability of a control to automatically silence the notification appliances
after a preset period of time.
Class A Circuit. An initiating device or notification appliance circuit within which all
components remain fully functional, even though a single open or ground exists in the circuit.
Class B Circuit. An initiating device or notification appliance circuit within which some or all
components may be disabled with a single open exists in the circuit.
Detector - FirePrint™. An intelligent fire detector that blends photoelectric, thermal and neural
network technologies for superior protection without false alarms.
Detector - Smoke, Photoelectric Type. A detector employing the photoelectric principle of
reflection or obstruction of light by smoke.
Detector - Thermal Type. An addressable thermal sensor that is programmable as either a
fixed temperature (135° F) or as a rate of rise detector.
Enable / Disable. Refers to the state of individual circuits (inputs and outputs) or logic
functions regardless of the presence of its corresponding modules.
End Of Line (EOL). A device used to terminate a supervised circuit.
Ground Fault. A trouble condition in which a low resistance has been detected between the
system wiring and conduit ground.
Hold-Thru Reset Condition. Refers to a condition where the hold-thru reset output will remain
in its current state before and after the reset until the OFF time delay has elapsed. Initiation of
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