Voice Input With Hands-Free Mode

During voice input with hands-free mode, the TCU receives the voice information from the hands-free microphone. The voice information is transmitted as low-frequency signals from the hands-free microphone to the MUX-DSP module. The signals are transmitted from the MUX-DSP module to the NAD/GSM 900/1800 module (transmitter and receiver module) for the GSM mobile phone network. The voice information is carried as high-frequency signals via the aerial wire to the GSM antenna on the vehicle exterior. The high-frequency signals are sent by the GSM antenna to the GSM mobile phone network.

• Functions are switched on and off using the transmit/receive button on the display. The transmit/receive button is illustrated on the following displays:
  • On-board monitor
  • Multi-information radio
  • Multi-information display
  • Central information display
  • BMW Professional radio
  • BMW Business radio
  The following process is then implemented:
  • A radio which has been switched off is switched on by a switch-on signal.
  • A radio which is switched on is muted.
  • The hands-free mode is activated. The hands-free facility with digital full duplex transmission (the people in the conversation can speak and listen simultaneously) is enabled via the MUX-DSP module.
  Fig 1: Voice Input With Hands-Free Mode Flow Chart

  Courtesy of BMW OF NORTH AMERICA, INC.