Satellite digital audio radio (SDAR) control unit, component description - GF82.85-P-3121FL

Model 212 up to 3/1/15 as of model year 2011 up to model year 2016 with code 536 (SIRIUS satellite radio) 

Shown on model 212.0 

Fig 1: Satellite Digital Audio Radio Control Unit - Shown On Model 212.0

Courtesy of MERCEDES-BENZ USA

Location 

The SDAR control unit is located in the trunk on the left side behind the paneling on a bracket.

Tasks 

• Receive signals 
• Amplifying and decoding signals 
• Transmitting signals 

Receive signals 

Signals are read in via the following connections:

• Media Oriented System Transport (MOST) 
• Direct line 

Media Oriented System Transport (MOST) 

The SDAR control unit receives control signals from the COMAND controller unit (A40/3)

Direct lines 

• Circuit 30g
• Circuit 31
• Wake-up
• Multifunction antenna (A28/11) (for satellite signals and terrestrial signals)

Amplifying and decoding signals 

The SDAR control unit amplifies the satellite signals (Time Division Multiplex (TDM)) and the terrestrial signals (Coded Orthogonal Frequency Division Multiplex (COFDM)) and decodes them into PCM signals (pulse code modulation).

Transmitting signals 

• MOST 
• Direct line 

MOST 

• Audio signals to the sound system amplifier control unit (N40/3) (with CODE 810 (Sound system) or CODE 811 (Advanced sound system))
• Status of SDAR control unit, program-specific supplemental information (e.g. artist, track name and composer) as well as music genre (e.g. "ROCK", "NEWS") to the COMAND controller unit
• Demodulated and decoded digital S-band satellite and S-band terrestrial signals as digital traffic data signals (including weather data as of 01.07.2011) to the navigation unit (with CODE 512 (COMAND APS with DVD changer) or with CODE 527 (COMAND APS with single DVD drive (with navigation))) integrated in the COMAND controller unit

Direct line 

The SDAR control unit supplies the multifunction antenna with power via the signal line.