TV-mode, function

A2/42

A2/12

TV antennas on rear window

Low frequency (TV sound)

RGBS signals

A40/2

Diagnosis

Navigation computer

Central computer

Navigation CD drive

A40/3

Audio signal processing

RGBS signals

Low frequency signals (TV sound for headphones)

Infrared remote control

X11/4

Amplified antenna signals

CAN-B

RB CAN

D2B

Radio tuner

COMAND TV system block diagram,

without Code (810) Sound system up to 31.8.03

D2B Digital data bus

RB-CAN Robert Bosch CAN

NF Low frequency signals

RGBS signals Red-green-blue synchronous video signals

A40/3 COMAND operating, display and control unit

X11/4 Data link connector

A2/12 Rear window antenna amplifier module

A2/42 TV tuner

A40/2 Operating and display unit rear screen

A2/10

A2/12

TV antennas on rear window

A40/2

Audio signal processing

Central computer

DVD drive

A40/3

RB CAN

Infrared remote control

X11/4

Amplified antenna signals

MOST

N93/1

Block diagram of COMAND TV system, without sound system code (810) as of 1.9.03

MOST Media Oriented System Transport

RB-CAN Robert Bosch CAN

A40/3 COMAND operating, display and control unit

N93/1 Audio gateway control unit

X11/4 Data link connector

A2/10 TV tuner (MOST)

A2/12 Rear window antenna amplifier module

A40/2 Operating and display unit rear screen

 On vehicles as of 1.9.03, the TV tuner (MOST) (A2/10) is integrated in the Media Oriented System Transport (MOST). Thus, the data exchange (audio and video signals) with the other TV components takes place via this fiber optical cable.

 On vehicles as of 1.9.03, the audio gateway control unit (N93/1) is also installed as an interface between the Controller Area Network bus class B (interior) (CAN-B) and the MOST. The audio signals are then sent to the audio gateway control unit (N93/1) and output via the vehicle speakers.

TV system control

The TV tuner (A2/42) is controlled via the COMAND operating, display and control unit (A40/3). The communication between the COMAND operating, display and control unit (A40/3) and the TV tuner (A2/42) takes place via the Robert Bosch CAN (RB-CAN).

-------------------------------------------------------------------------------------------

The COMAND TV system has the following features:

 4-way TV antenna diversity

 Multistandard capability, i.e. Color decoder for NTSC, PAL and SECAM standard with automatic detection

 Videotext decoder

 10 memory locations for the station list sorted by reception field strength and 10 further memory locations for freely selectable stations

 SCAN function (the stations are played in succession)

 On Screen Display (OSD) function (text displays on the screen)

 The COMAND TV system provides a facility for connecting other video sources such as a video recorder or Camcorder. The relevant connectors are provided on the TV tuner (A2/42).

-------------------------------------------------------------------------------------------

TV reception

The 4 TV antennas in the rear window receive the TV high-frequency signals completely independent from one another. The video and sound signals are modulated upon these high-frequency signals. The rear window antenna amplifier module (A2/12) filters the frequencies of the TV frequency bands from the high frequency signals and amplifies them. The amplified signals are led to the TV tuner (A2/42) via 4 separate coaxial cables.

The TV tuner (A2/42) selects the strongest of the incoming antenna signals (antenna diversity), selects the required transmitter and then demodulates the TV sound and TV video signals in accordance with the relevant transmission standard (e.g. NTSC). The video and sound signals prepared in this way are transferred as red-green-blue synchronous video signals (RGBS) as well as low-frequency signals (LF) for the audio signals (TV sound) to the COMAND operating, display and control unit (A40/3) and the operating and display unit rear monitor (A40/2).

-------------------------------------------------------------------------------------------

TV picture display

up to 31.8.02

The TV picture is only shown on the display of the COMAND operating, display and control unit (A40/3) under the following prerequisites:

 The parking brake has to be actuated and the selector lever has to be in the "P" or "N" position (both pieces of information come via the CAN-B).

as of 1.9.02

The display in the COMAND operating, display and control unit (A40/3) switches off automatically at a speed of v > 8 km/h. In contrast to this, the pictures are also displayed on the rear monitor operating and display unit (A40/2) while driving. The TV system can then also be operated from the rear by remote control.

TV sound playback (up to 31.8.03)

The TV tuner (A2/42) forwards the TV audio signal to the COMAND operating, display and control unit (A40/3) via separate lines.

-------------------------------------------------------------------------------------------

The signals are then amplified and converted into acoustic signals by the vehicle speakers. 2 sets of headphones can be connected to the operating and display unit rear monitor(A40/2). Only the TV sound can be heard on these headphones, regardless of the audio source that is being played on the vehicle speakers.

 With code (810) Sound system, the TV audio signals are sent from the COMAND operating, display and control unit (A40/3) via the Digital Data Bus (D2B) to the sound amplifier (A2/13), where they are received,amplified and then converted into acoustic signals via the vehicle speakers.

TV mute function (as of 1.6.01)

The mute status of the audio sources (muting) is maintained if it was activated before switching off.

Displaying mute status in the TV screen

If audio sources are muted, a symbol appears in the top right of the display.

To be able to display on the TV screen that the mute function is active, the corresponding message has to be transmitted to the TV tuner (A2/42).

The setting which was performed last before switching off the ignition, is adopted when the ignition is switched on again.