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

Model 218 up to model year 2015 with code 536 (SIRIUS satellite radio) 

Illustrated on model 218.3 

Location 

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

Task 

The SDAR control unit has the following tasks:

• Receive signals 
• Amplifying and decoding signals 
• Transmitting signals 

Receive signals 

The SDAR control unit receives signals 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.

Direct lines 

The SDAR control unit receives the following signals via direct lines:

• Wake-up signal from COMAND controller unit (A40/3)
• Satellite radio signals and terrestrial radio signals from the multifunction antenna (A28/11)

Amplifying and decoding signals 

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

Transmitting signals 

The SDAR control unit transmits signals via the following routes:

• Direct line 
• MOST 

Direct line 

• Multifunction antenna (power supply to antenna, power supply via antenna input)

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.b. "ROCK", "NEWS") to the COMAND controller unit
• Demodulated and decoded digital S band satellite as well as S band terrestrial signals as digital traffic data signals of Real Time Traffic Data (RTTD) (as of 1.7.11, also including weather data) to the navigation unit integrated in the COMAND controller unit (with CODE 512 (COMAND APS with DVD changer) or with CODE 527 (COMAND APS with single DVD drive (with navigation)))

Wiring diagram for satellite digital audio radio system control unit (SDAR)

PE82.60-P-2301-97XAA