The GE Crystal Shock Sensor can detect the following:

• The vibrations made by an intruder trying to break a window or door.
• A window or door opening.
• Tampering with the sensor, such as removing the cover 
  

Vibrations cause a momentary open circuit in the shock element of the sensor. The circuit closes again when the vibration stops. The sensor microcontroller "sees" the open/close action as a pulse, causing the sensor to transmit an alarm signal. The sensor has two different detection modes:

• Gross Attack - detect a violent blow sufficient in length to trip sensor.
  
• Pulse Count - detect a sufficient number of less violent blows (rapping or tapping).

The sensor includes an internal magnetic reed switch that must be disabled if it is not used.
A cover tamper provides additional security if an intruder tries to disable or damage the sensor.