Manual Emergency Call Button

The manual emergency call button (1) is a direct input (hardwired) to the telephone control unit. When a call is made the LED (2) illuminates.

Once the call is initiated there is no way to cancel.

The automatic emergency call is made by the SIM after a collision, based on the severity. The signal from the SIM to the TCU is passed on over a dedicated circuit. Refer to ISIS for more detail.

Fig 1: Identifying Manual Emergency Call Button

Courtesy of BMW OF NORTH AMERICA, INC.