A security alarm is a system designed to detect intrusions, such as unauthorized entry, into a building or other areas, such as a home or school. Security alarms protect against burglary (theft) or property damage, as well as against intruders. Examples include personal systems, neighborhood security alerts, car alarms, and prison alarms.
Some alarm systems serve a single purpose of burglary protection; combination systems provide fire and intrusion protection. Intrusion-alarm systems are combined with closed-circuit television surveillance (CCTV) systems to record intruders' activities and interface to access control systems for electrically locked doors. There are many types of security systems. Homeowners typically have small, self-contained noisemakers. These devices can also be complicated, multirole systems with computer monitoring and control. It may even include a two-way voice which allows communication between the panel and monitoring station.
Harpenden (/ˈhɑːrpəndən/) is a town and civil parish in the City and District of St Albans in the county of Hertfordshire, England. The population of the built-up area was 30,240 in the 2011 census, whilst the population of the civil parish was 29,448. Harpenden is a commuter town, with a direct rail connection through Central London and property prices well over triple the national average.