Telephone Control Unit

The telephone control unit is located in the left side of the luggage compartment. It is responsible for:

• Executing the automatic and manual emergency call (integrated with navigation).
• Controlling charging and cycling of the handset batteries when plugged into the vehicle.
• Providing the microphone signal as a MOST bus telegram.
• Integration of the telephone into the vehicle iDrive system via the MOST network.
  Fig 1: Identifying Telephone Control Unit Connector Pins

  Courtesy of BMW OF NORTH AMERICA, INC.