Satellite digital audio radio (satellite radio) (SDAR) function - GF82.60-P-3021G

MODEL 463.249 /271 up to 31.8.08 as of model year 2007 

Fig 1: Satellite Digital Audio Radio Function Diagram

Courtesy of MERCEDES-BENZ USA

Function requirements 

• C. 15R On
• The Cockpit Management and Data System (COMAND) is authorized and working correctly.
• The SDAR antenna is working without problems

General 

The SDAR control unit enables "Sirius Satellite Radio" provider channels to be received. The satellite digital audio radio (SDAR) (satellite radio) system is actuated using the COMAND operating, display and controller unit. The data or displays required for operation are shown on the display of the COMAND operating, display and controller unit and also on the multifunction display (A1p13) in the instrument cluster.

The display of audio, telephone and navigation data in the multifunction display in the instrument cluster is only available as of model year 07.5, YoM 07.

Operating instructions 

The SDAR can be operated using the:

• Left multifunction steering wheel button group
• Right multifunction steering wheel button group
• COMAND operating, display and controller unit buttons
• Voice control system (VCS [SBS])

Operation of the audio, telephone and navigation components via the multifunction steering wheel button group and the voice control system is only available as of model year 07.5, YoM 07.

SDAR function sequence 

The Sirius satellite radio signal is broadcast 3 times to achieve a diversity of channels (using two satellites and one terrestrial transmitter). The SDAR antenna receives these three channels.

The SDAR antenna routes the signals over a coaxial cable to the SDAR control unit. The SDAR control unit receives and decodes the signals. Finally, the SDAR control unit transmits the decoded, digital radio signals over MOST to the COMAND operating, display and controller unit.

The COMAND operating, display and controller unit actuates the sound system amplifier to output the audio at the speakers.

Diagnosis 

Diagnosis is actuated by the electronic ignition switch control unit via the diagnostic CAN to the COMAND operating, display and controller unit.

All other control units on the MOST ring are also diagnosed via this interface. This means that the COMAND operating, display and controller unit forms a diagnosis gateway.