Burglar alarms are systems designed to detect unauthorized entry into a building or area. They consist of an array of sensors, a control panel and alerting system, and interconnections. Sensors detect intruders by many methods such as monitoring door and window contacts, by passive infrared motion detectors, ultrasound, vibration, electric or magnetic fields, or microwaves. Sensors may be directly wired to a control panel that provides sensor power, or may communicate wirelessly.
Burglar alarms are used in residential, industrial, and commercial properties for protection against theft or property damage. Mobile alarm systems protect vehicles and their contents. Prisons and military facilities use intrusion detection systems for security and control of access. There is hundreds of alarm monitoring companies providing real-time monitoring services for varieties of users on monthly contractual obligations.