Transcription: Many buildings now utilize sophisticated alarm systems to protect them against intruders. There are many different varieties of alarm system, but they all function on similar principles. An alarm system utilizes a control panel, a sounder which is either a bell or a siren, and various detectors. There are detectors for almost every situation. Passive infrared detectors for movement, magnetic contacts for windows and doors, foil strips and brake glass detectors for window smashes and pressure mats for under carpets and other floor coverings.
(.mp3)