security alarm
An automated or user-activated system to warn off intruders or criminals and to alert police.
A security alarm is a system installed to warn off criminals such as burglars, robbers, intruders, or invaders and to alert police or other security forces of the threat. The alarm may be user-activated (e.g. an alert button) and/or rely on automatic detectors such as door alarms, window alarms, or motion detectors. Normally these alarms produce a loud noise when activated, and they are frequently programmed to alert civil authorities by telephone of the location of the violation.
This feature is similar in many ways to a fire alarm system, except in its purpose and its methods of detection.
Manual activation and automatic detection are both permitted. The security purpose distinguishes the system from a fire alarm, while loud sound and telephone notification are common implementations rather than required in every installation.
