L
Labeled
Equipment or materials that have a label, symbol, or other identifying mark of an organization with authority and jurisdiction that are concerned with product evaluation and maintains periodic inspection of the production of the labeled equipment or materials. The manufacturer who is labeling indicates compliance with appropriate standards or performance in a specified manner.
Late to Close Output
A specified output on a panel that is turned on any time a programmed area remains disarmed past the scheduled closing period. The output is turned off when the area is armed, the closing schedule is extended, or the schedule is changed.
LCD (Liquid Crystal Display)
A type of backlit display used in DMP keypads to make them easier to read.
Lead
Pronounced leed
A wire conductor leading to or from a terminal.
Lead-Acid Battery
A storage battery where the cells contain lead plates immersed in an electrolyte (like sulfuric acid). The positive plate contains lead peroxide and the negative plate contains spongy lead. Rechargeable, lead-acid batteries are recommended for use with DMP equipment.
Leased Line
A dedicated circuit, typically supplied by the phone company, that permanently interconnects two or more user locations and provides uninterrupted dedicated service.
Light Emitting Diode (LED)
A diode that emits light when energized.
Light Scattering
The action of light being reflected and/or refracted off particles of combustion for detection by a photoelectric smoke detector.
Line Security
The signaling system degree of protection that connects the subscriber system to the monitoring center alarm company. Two levels of line security, standard and encrypted, are recognized by UL.
Line Seizure
The function of a digital communicator to take control of the premise phone line by means of a relay.
Line Supervision
The electrical supervision of a wire run to detect tampering (a cut or shorted wire). Line supervision usually requires a terminating element at the end of the monitored wire zone.
Line Fault
A discontinuity in a transmission line, resulting in signal loss at the circuit receiving end.
Line Voltage
The voltage existing in a main cable or circuit, such as at a wall outlet.
Listed
Equipment or material included in a list published by an organization acceptable to the authority having jurisdiction and concerned with evaluation of products and services, that maintains periodic inspection of listed equipment or materials or periodic evaluation of services and whose listing states either that the equipment, material, or service meets identified standards or has been tested and found suitable for a specified purpose.
Local Alarm
A visual or audible signaling device located at a monitored door, window, or other opening.
Local Area Network (LAN)
A network in one area, such as a building or group of buildings.
Local Printer
A serial printer that can be connected to certain DMP Command Processor panels to provide a printout of system events. This feature can allow business owners to track employee activity, check system arming and disarming times, or monitor other events of their security or fire system.
Local System
An alarm system that rings a local sounding device in the event of an alarm and does not communicate alarms to the monitoring center.
Lock
A device for security on a door in the closed position against unauthorized or forced entry. It requires actuation to project or to retract its bolt.
Loop
See Zone.
Loss
Reduction in signal strength, expressed in decibels. This is the opposite of gain.
LX-Bus™
A DMP four-wire data bus where the user can connect addressable zone, output, or wireless expanders. The LX-Bus can be connected directly to a panel.