CD player mode function

Diagnostic test connector (X11/4)

Navigation processor with
GPS receiver and gyrosensor

Diagnosis

Traffic data
memory (A2/43)

Central
processor

Radio tuner

Audio
signal processing

Instrument cluster (A1)

Multifunction steering wheel

Amplifier for

sound system

(N40/3)

Vehicle loudspeaker

D2B mobile telephone
interface (A59/1)

CD player
with changer
(in the trunk) (A2/6)

D2B

CD drive

Operating ,
display and
control unit COMAND (A40/3)

AF signals

CAN-(A40/3-A1)

COMAND with CD changer block circuit diagram, depicted with the following equipment:

 Sound system (code 810)

 D network mobile telephone (D2B) (code 317)

The marked components are those which are significantly involved in the operation of the CD.

Abbreviations

D2B Digital Data Bus

AF Audio frequency (20 Hz... 20 kHz)

CD changer operation (with code 819)

The CD player with changer (in the trunk) (A2/6) is controlled by the COMAND operating, display and control unit (A40/3). The control signals and the audio data from the CD player with changer (in the trunk) (A2/6) are transmitted via the D2B.

 Only 12 cm CDs may be inserted into the CD player with changer (in the trunk) (A2/6); no 8 cm CD adapters may be used.

In the case of the sound system (code 810) (as depicted above), the sound system amplifier (N40/3) carries out final amplification of the audio signals. The signal is transmitted in analog form between A40/3 and N40/3 (not via D2B). The amplified signals are emitted via the vehicle's loudspeaker system.

 If the vehicle is equipped with the amplifier for the sound system (N40/3), the COMAND operating, display and control unit (A40/3) must be accordingly encoded with the aid of the STAR diagnosis tool, as interference otherwise occurs on emission of the audio signals.

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In combination with the CD player with changer (in the trunk) (A2/6), COMAND provides the following functions:

 Scan function
The titles of a CD, or the first title of each of the CDs within the entire magazine, are played for 8 s. After this has been run through completely, the scan function is automatically terminated.

 Random function
All titles of a CD or the entire CD magazine are played according to the random principle.

 Repeat function
Alternatively, a title, a CD or the entire CD magazine is repeated.

 Fast forward/reverse (music search)
The music played during fast forwarding/reverse is audible. Certain parts of a title can therefore be specifically played or skipped.

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CD title allocation function

Each CD contains a firmly stored Table of Contents (TOC) record. On the basis of this record, COMAND clearly recognizes the relevant CD, and is able to automatically designate this following non-recurring title allocation by the user (even if the CD is subsequently inserted in another CD magazine).

The TOC record additionally contains information regarding the number of titles on a CD and the CD's total playing time.

CD operation with the integrated CD drive

The COMAND operating, display and control unit (A40/3) is equipped with an integrated CD drive, which alternatingly serves for loading the navigation data or for audio CD playback.
No audio CDs can be played back during navigation mode.