Detection Devices, or how is an intruder detected? What is door contact?
A contact (in its simplest form) is a metal switch, fitted to the doorframe that is kept closed by a magnet fitted to the door. In most cases these are fitted flush into the frame and door but some are fitted surface. Heavy Duty contacts can be fitted to large doors (e.g. garages) and special contacts are available for Roller Shutters.
