Battery Back-up
A secondary power source used to provide power in the event the main power source fails. A battery backup is intended for temporary use and to ensure the continual operation duringa power interruption of the main source. Typically, battery backups are used in computers, alarm clocks, and home security systems, where interruption of power would cause a loss of data, service or human harm. .

Break-in
When someone illegally enters a residence, car, office or other enclosed property using the slightest amount of force (such as pushing open a door) without consent. If there is no intent to commit a crime, i.e. breaking and entering, it may be considered illegal trespassing. If the intent was to commit a crime, it could be considered burglary. .

Burglar Alarm
A loud warning signal produced by an electronic sound designed to alert the user, neighbors, home security monitoring system and/or police to a specific danger. Sensors are connected to a control unit. Many security sensors are used to indicate the opening of a door or window or detect motion.