Voice Output In Privacy Mode

In voice output in privacy mode, high-frequency signals are received by the GSM antenna and transmitted to the NAD/GSM 900/1800 module (transmitter and receiver module) for the GSM mobile phone network 900/1800 MHz in the Telematic Control Unit (TCU). From this module, the high-frequency signals, with the voice information contained in them, are sent to the Bluetooth module in the TCU. The high-frequency signals are transmitted from the Bluetooth module in the TCU to the Bluetooth antenna on the TCU.

A ringing tone is produced as an audible signal at the same time. The ringing tone sent by the audio system indicates an incoming call.

Low-frequency signals are sent via the MUX-DSP module to the audio system to produce the ringing tone. The loudspeakers in the audio system convert the low-frequency signals into a single signal sequence and emit these into the vehicle interior.

• The incoming call is accepted by pressing the transmit/receive button on the Bluetooth handset. The following process is implemented:
  • A radio which is switched on is muted by the signal to the radio mute (mute signal).
  • Hands-free mode is deactivated. The hands-free facility with digital full duplex transmission (the people in the conversation can speak and listen at the same time) is deactivated via the MUX-DSP module simultaneously.
  • The voice information is sent from the Bluetooth antenna as high-frequency signals in the Bluetooth standard.
  • These signals are received by the Bluetooth handset and are output through the loudspeaker in the Bluetooth handset as voice information.
  Fig 1: Voice Output In Privacy Mode Flow Diagram
  Courtesy of BMW OF NORTH AMERICA, INC.