A security alarm system can detect unauthorized entry into a building or other areas such as a home or school. Security alarms installed in residential, commercial, industrial properties protect against burglary or property damage, also provides personal protection against intruders. Car alarms also aid in the protection of vehicles and their contents. Security systems also used in prisons to keep the inmates under control. Some alarm systems only provide burglary protection, while some others provide both fire and the intrusion protection. Security alarms combined with CCTV systems to record intruders’ activities and to access control systems for electrically locked doors.