TV mode, function

Data link connector (X11/4)

Navigation processor

Top left rear window
antenna amplifier (A2/8)

Diagnosis

Traffic data memory (A2/43)

Central
processor with graphic signal processing

Rear window antenna amplifier
bottom right (A2/25)

Radio tuner

Audio signal processing

Instrument cluster (A1)

Multifunction steering wheel

Vehicle loudspeaker

TV tuner
(A2/42)

RGBS

Antenna amplifier
rear window, top right (A2/9)

LF signal (TV sound)

TV4

TV 3

TV1/2

CD drive

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

AF signals

RB CAN

CAN-
(A40/3-A1)

COMAND TV system block diagram

The marked components are the components which are used primarily for TV operation .

RGB red/green/blue synchronization signals

TV1..4 Television antennas

Abbreviations:

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

RB-CAN Robert-Bosch-CAN

TV system design

In the TV system the following components work together:

 COMAND operating, display and control module (A40/3)

 TV tuner (A2/42) with installed video decoder

 TV antennas of rear window in combination withrear window antenna amplifier module (A2/12)

 Navigation processor for transmitting control commands from theCOMAND operating, display and control module (A40/3) via the RB CAN bus and for generating the control displays.

 Moreover, theCOMAND TV system offers the possibility for connecting additional video components such as video recorder and camcorder. The corresponding connections are already preequipped on the TV tuner (A2/42). The TV system can also be operated from the rear of the vehicle using a remote control.

TV system control

The TV tuner (A2/42) is controlled by the COMAND operating, display and control module (A40/3).

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The data telegrams are transmitted from the COMAND operating, display and control module (A40/3) via the RB-CAN to theTV tuner (A2/42).

TV reception, function

The four TV antennas in the rear window receive the high frequency TV signals independently of one another Their signals are amplified by therear window antenna amplifier module (A2/12) and transmitted to the TV tuner (A2/42) over four co-axial cables

TheTV tuner (A2/42) selects the strongest of the four antenna signals (antenna diversity). Then it separates the selected TV stations from the received signal spectrum and demodulates the TV video and TV audio signals in the video decorder.

The signals are transmitted as red, green,blue and synchronization signal (RGBS) as well as AF audio signal via a separate line each to the COMAND operating, display and control module (A40/3).

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Generating control and entry displays

The control and entry displays for the TV system are generated by the navigation processor as RGB color signals (R= red G=green,B=blue) and displayed on the COMAND operating, display and control module (A40/3) display.

 The TV picture is only displayed on the operating and display unit display when the vehicle speed is below 8 km/h.

The information for this purpose is transmitted via the CAN bus passenger compartment.

TV audio generation and output

The TV tuner (A2/42) with installed video recorder transmits the demodulated TV audio signal to the COMAND operating, display and control module (A40/3) via a separate line for the left and right stereo channel.There the signals are amplified and converted into acoustic signals by the vehicle loudspeakers.

TV mute function (as of 01.06.01)

The mute state of the audio sources is maintained, if activated before switching off.

Displaying mute state in TV screen

When set to mute a symbol is indicated on the display at top right .

To indicate the mute status in the TV display it is necessary for the mute status to be transmitted to the TV tuner with a newly generated command.

The last setting before switching off the ignition is resumed when the ignition is switched back on

 If the vehicle is equipped with a sound system (code 810), the voice signals are transferred by the COMAND audio signal processing system to the sound system amplifier (N40/3) , where they are amplified and output by the vehicle loudspeakers.