The interior monitoring is an additional security system that triggers the alarm if unauthorised access to the vehicle is detected in the area of the windows.
The transceivers work ultrasonically. The transmitter transmits at a specific frequency into the monitoring area. The receiver receives the corresponding echo signal. Here, the signals are converted into digital values and compared with the values from the signals received previously. If there are significant differences between the two, a trigger signal is sent to the GEM.
As the period during which no movement is detected increases, so the sensitivity of the sensors increases.
A special horn is installed for vehicles that have to comply with the Thatcham category I (CAT 1) insurance standard. This horn has its own voltage supply from an integrated battery.
This ensures that the alarm horn will still be powered even if the vehicle battery has been disconnected.