An intrusion detection alarm system is a technical system for detecting and reporting unauthorized physical entry into buildings or rooms. These systems combine sensors (motion detectors, magnetic contacts, glass-break detectors) with a control panel and notification devices.
In the ISMS context, alarm systems are among the physical security measures under ISO 27001 Annex A (A.7). They protect server rooms, data centers, and archives from unauthorized access. Modern systems integrate with access control and video surveillance. Regular maintenance and testing are essential: an alarm system with untested sensors provides only an illusion of security.