An alarm device or system of alarm devices gives an audible, visual or other form of alarm signal about a problem or condition. Alarm devices are often outfitted with a siren.
Burglary/Intrusion alarm systems have devices connected to them to detect the Theft. Below is a list of common devices found on a Burglar Alarm Systems.
Hooter/Siren, Surface Mount Switch, Recessed Mount Switch, Shutter Switch, Panic Switch, PIR Motion Sensor, Vibration Sensor, Glass Break Detector, Beam Sensor, Boundary Detector.