Notes on D2B ring - AH82.70-P-0001-03IA

MODEL 215, 220 with CODE 316 (MB D-net telephone (D2B)) with CODE 317 (D-net portable CTEL (D2B)) with CODE 347 (EMERGENCY CALL system (D2B)) 

1. The user components in the D2B ring in this case are:
2. Radio (A2) or COMAND operating, display and controller unit (A40/3)
3. Sound amplifier (A2/13)
4. CD changer (A2/6)
5. D2B interface for fixed installation telephone (A59) (for code 316 only) or

D2B interface for cell phone (A59/1) (Only with code 317)

or 

Control unit for TELE AID (A35/8) (code 347)

1. The information in the D2B ring only flows in one direction (arrows). The information enters in the white insert (white) in a fiber optic cable module M1 to M3 and exits again in the red insert (red) at the next ring component. The D2B ring only is capable of functioning as a closed circuit.

1. Before the D2B ring can be expanded it is first necessary to determine the current vehicle configuration
   Fig 1: Identifying Radio Communication Diagram

   Courtesy of MERCEDES-BENZ USA

1. Determine and note actual configuration in vehicle Configuration with maximum equipment 

At the same time they correspond to the ring sequence and the direction of the information flow (from 1 to 7) and they must  be complied with when retrofitted.

1. 1a Head Unit (HU) radio (standard equipment)

   or 

2. 1b Head Unit (HU) COMAND (SA)
3. 2 Sound amplifier (SA)
4. 3 CD player with changer (SA)
5. 4 Telephone (fixed installation or cell phone)

   or  TELE AID (SA)

6. 5 Voice Control System (SA)
7. 6 Cell phone option (SA)
8. 7a Head Unit (HU) radio (standard equipment)

   or 

9. 7b Head Unit (HU) COMAND (SA)

   If special equipment (SA) is discontinued the corresponding item is deleted and this results in a new sequence.

   Fig 2: Identifying Sound Amplifier And Voice Control System

   Courtesy of MERCEDES-BENZ USA

1. Determining the special equipment in the vehicle:
   1. Sound amplifier (N40/3): Open trunk, left side
   2. CD player with changer (A2/6): Open trunk, left side
   3. Telephone (fixed installation or cell phone): Open stowage compartment of armrest
   4. Voice Control System: Switch on telephone, press button for Voice Control System (S93/2) on multifunction steering wheel (model 220), operate switch for Voice Control System (S93/2) on steering column tube (model 215), whistling noise sounds, Voice Control System present
   5. Cell phone option: Open glove compartment
   6. TELEAID emergency call system switch (S93/3) present