Rear Entertainment, Function - GF82.90-P-0002GD

MODEL 204.9 with CODE (864) Rear entertainment system 

Function requirements, general 

• Circuit 30g ON and telematics CAN (CAN A) active for t = 10 min

Rear entertainment system, general 

The rear entertainment system provides the rear passengers with audio/visual entertainment. DVD players, MP3 players, video cameras, games consoles and so on can be connected to the rear entertainment system via an AUX jack.

The rear entertainment system uses primarily the following components:

• DVD player
• Left rear display
• Right rear display
• Remote control
• Infrared (IR) headphones (cordless) or corded headphones

The following components are also used by the rear entertainment system but are not essential for using the rear entertainment system:

• COMAND control unit
• Audio/COMAND control panel
• Sound system amplifier control unit (with code (810) Sound system)
• Vehicle speaker system

The rear entertainment system allows the following audio or video sources to be used:

• Audio CD/audio DVD or MP3
• DVD video
• AUX

The DVD player and rear display are subscribers on the telematics CAN and communicate with the audio equipment.

In AUX mode, external video sources can be used. They are connected either to a rear display or to the DVD player.

On vehicles with code (527) COMAND APS with single DVD drive (with navigation) or code (512) COMAND APS incl. DVD changer or code (528) COMAND incl. DVD changer, the rear entertainment system provides access to the active audio or video application of the COMAND controller unit.

This functionality must be enabled via the COMAND controller unit.

This audio or video application is actuated via the COMAND controller unit. The rear entertainment system does not provide any selection options here.

The rear entertainment system can be operated with the associated remote control. The rear passengers can select menus on the currently active rear display using this remote control. The control signals from the remote control are transmitted to the currently active rear display via IR interfaces.

The audio signals are then transmitted from the rear display to the headphones (cordless) via IR interfaces.

If corded headphones are used, the audio signals are transmitted as analog signals from the rear display to the headphones via a cable.

The rear entertainment system consists of the following subfunctions:

• Switch on/off characteristics 
• System settings 
• Disk applications 
• AUX applications 

Switching on and off characteristics 

The rear entertainment switch on/off characteristics function consists of the following subfunctions:

• Function sequence for switching on/off using the remote control 
• Function sequence for automatic switch off 

Function sequence for switching on/off using the remote control 

The left rear display or right rear display can be selected with the knob on the remote control. The rear entertainment system can be switched on and off with the button the remote control.

The control signals from the remote control are transmitted to the appropriate rear display via IR interfaces.

The rear display then sends an ON signal via the telematics CAN to the DVD player, which is then activated. At the same time, the rear display generates for approx. t = 6 s the audio and video signals for the corporate identity display on the screen.

The rear entertainment system is also switched off using the ON/OFF button on the remote control.

The control signal from the remote control is transmitted to the appropriate rear display via IR interfaces.

The rear display then sends the OFF signal via the telematics CAN to the DVD player, which then switches off. The application last run is stored in the rear display and continued the next time the rear display is switched on.

Function sequence for automatic switch off 

When the transmitter key (A8/1) is removed from the electronic ignition lock control unit (circuit 15C OFF), the message announcing that the transmitter key has been removed and the query as to whether the application is to be continued appear on the active rear display. If the "OK" button on the remote control is then pressed, the active application can be continued if called up within approx. t = 30 min (timeout).

The rear entertainment system is then switched off and the application last run is stored in the rear display. If the "OK" button is not pressed, the rear entertainment system is switched off immediately.

The status of circuit 15 is read in over the following paths:

• Electronic ignition switch control unit
• Interior CAN
• Audio unit
• Telematics CAN
• DVD player and rear display

System settings 

The "System" base function can be used to select the following items and to make settings:

• "System settings"
• "Display off"

The screen-related settings such as design and language can be set in the system settings menu.

All system settings can be made individually for each rear display without influencing the other rear display.

The following settings can be made:

• "System settings"
  • "Language"
  • "Day design"
  • "Night design"
  • "Automatic"
  • "Brightness" (background illumination of the rear display)
• "Display OFF" (screen of the rear display is switched off; the system is, however, not switched off. Pressing the "OK" button on the remote control switches the screen on again)

With overvoltage or undervoltage, the rear entertainment system switches off automatically.

Function requirements for disc applications 

• Audio source inserted in DVD drive of DVD player

Disk applications 

The rear entertainment system allows the following audio or video sources to be used:

• Audio CD/audio DVD or MP3
• DVD video
• AUX

The audio or video source is detected automatically.

A basic screen is shown in the left rear display or in the right rear display according to the audio or video source. The rear passengers can then use the audio or video source with the aid of the remote control.

On vehicles with code (527) COMAND APS with single DVD drive (with navigation) or code (512) COMAND APS incl. DVD changer or code (528) COMAND incl. DVD changer, the rear entertainment system provides access to the active audio or video application of the COMAND controller unit. This functionality must be enabled via the COMAND controller unit.

The DVD drive integrated in the DVD player decodes the digital data of the inserted audio or video source and passes this data on internally to the DVD player. The DVD player generates analog audio and video signals from the digital data. The audio signals are then transmitted to the appropriate rear display via a stereo line.

The rear display generates digital audio signals from the analog audio signals for output on the headphones (cordless). These signals are transmitted to the headphones (cordless) via IR interfaces.

If corded headphones are used, the audio signals are transmitted as analog signals from the rear display to the headphones via a cable.

The audio output volume on cable connected headphones can be adjusted with the aid of the remote control. The volume of audio output over the headphones (cordless) can only be adjusted using the volume control on the headphones (cordless).

The analog video signals are transmitted from the DVD player to the rear display via the Y brightness (luminance)/C color information (chrominance) (Y/C) line. From the analog video signals, the rear display generates digital signals for display on the screen.

Playback errors can occur when copied audio or video sources are played back. The large number of available data storage devices means that it is impossible to guarantee that the rear entertainment system can play back all copied CDs/DVDs. DVD videos conforming to the "PAL" or "NTSC" standard which fulfill the following conditions can be played back:

"Region code 2" (for Europe)

"Region code 0" (no region code)

On vehicles without code (494) USA version, the rear entertainment system is factory-set to "Region code 2". The country-specific coding is performed using the IS tester.

On vehicles with code (527) COMAND APS with single DVD drive (with navigation) or code (512) COMAND APS incl. DVD changer or code (528) COMAND incl. DVD changer, audio output is also possible over the vehicle speaker system.

The DVD player sends the analog audio signals to the COMAND control unit via stereo line for audio output on the vehicle speaker system. On vehicles without code (810) Sound system, the COMAND control unit sends the audio signals to the speaker system via direct lines. On vehicles with code (810) Sound system, the COMAND controller unit passes on the audio signals via Media Oriented System Transport (MOST) to the sound system amplifier control unit, which amplifies these signals and outputs them over the speaker system:

Detailed on the speaker system is given in the document "Speaker output, function".

Function requirements for AUX applications 

• Audio or video unit connected to the AUX jack of the left rear display, of the right rear display or of the DVD player

AUX applications 

The AUX jack on the DVD player or on a rear display can be used to connect external audio or video units (e.g. portable DVD player, video camera, MP3 player or games console) to the rear entertainment system.

On vehicles with code (527) COMAND APS with single DVD drive (with navigation) or code (512) COMAND APS incl. DVD changer or code (528) COMAND incl. DVD changer, the rear entertainment system provides access to the active audio or video application of the COMAND controller unit. This functionality must be enabled via the COMAND controller unit.

The connected audio or video unit is detected automatically. As soon as it has been detected, this is indicated in the "Aux" menu on the active rear display.

No equipment-specific interface is provided by the respective display or by the DVD player in the "AUX" menu item for these video units or audio unit. The audio and video units are operated at the units themselves. The active rear display shows a graphic depiction of the data received. If a video source is connected it is recognized automatically. The background (headphones) on the display disappears and the video source is played back. If an audio source is connected, the background remains on the display and the audio source is played back. In the "AUX" menu item, the recognized video or audio source is shown on the switched-on display.

If a video unit or audio unit is connected to the AUX jack of a display or the DVD player, the depiction in the "AUX" menu item takes place on whichever display is switched on.

On vehicles with COMAND controller unit each video or audio source for the COMAND controller unit can be selected. The corresponding screen is displayed in the "COMAND" menu item on the respective switched-on display according to whether a video or audio source was selected through the COMAND controller unit. Only information on the application currently active is displayed (e.g. radio station). The video or audio source of the COMAND controller unit is operated via the COMAND controller unit. Simple control functions on the COMAND (e.g. previous/next track) can also be made from the respective display.

The "AUX" menu item is only active on a display that is switched on. It is only necessary to select the respective display using the "Roller" control when the "AUX" menu item is operated via the remote control.

The "AUX applications" function in the rear entertainment is made up of the following subfunctions:

• Video unit detected function sequence 

D Audio unit detected function sequence 

D Function sequence for transferring audio and picture signals for AUX applications 

Following this, extensive information is available on operating the AUX applications:

D Operating instructions for AUX applications 

Video unit detected function sequence 

The display or the DVD player automatically recognizes the connection of a video unit to an AUX jack.

The display uses the transmitted data from the video unit to generate the analog or digital video and audio signals and the digital interface of the "AUX" menu item on the display.

The respective display shows the menus and their submenus in the "AUX" menu item (see operating instructions).

Selection of extra operations or settings can now be made using the listed controls on the remote control (see operating instructions).

The remote control signals are sent over the remote control's infrared (IR) interfaces and the respective display.

Audio unit detected function sequence 

The display or the DVD player automatically recognizes the connection of an audio unit to an AUX jack.

The display uses the transmitted data from the audio unit to generate the analog or digital audio signals and the digital interface of the "AUX" menu item on the display.

The respective display shows the menus and their submenus in the "AUX" menu item for the rear passenger (see operating instructions). Selection of extra operations or settings can now be made using the listed controls on the remote control (see operating instructions). The remote control signals are sent over the remote control's infrared (IR) interfaces and the respective display.

Function sequence for transferring audio and picture signals for AUX applications 

After receiving the analog picture signals from the following AUX jacks via the following routes, the respective display generates the digital picture signals:

• "COMAND" (with COMAND controller unit):
  • COMAND controller unit
  • Y/C line
  • DVD player
  • Y/C line
• Display AUX (AUX jack of the left rear display or AUX jack of the right rear display):
  • Direct lines
• DVD player AUX:
  • DVD player
  • Y/C line

The generated digital picture signals are displayed via the respective display. After receiving the analog audio signals via the following route, the respective display generates the digital audio signals:

• "COMAND" (with COMAND controller unit):
  • COMAND controller unit
  • Stereo line
  • DVD player
  • Stereo line
• Display AUX (AUX jack of the display):
  • Direct lines
• DVD player AUX:
  • DVD player
  • Stereo line

These digital audio signals are sent over the radio interfaces of the respective display and the corresponding headphones to these headphones (cordless).

Volume can only be adjusted via the volume control integrated in the respective headphones.

In the headphones sockets integrated into the displays for the connected headphones (cable-connected), the analog audio signals are sent from the display over the headphones cable to the headphones.

Operating instructions for AUX applications 

Video or audio output is performed automatically.

If a video unit is detected or a video source of the COMAND controller unit, the downsized video picture is shown in the application field and the "AUX" menu item, partitioned as follows, with the relevant menus on each display:

• Application bar:
  • "Disk", "TV", "AUX" and "System"
• Scaled down video image and "Full screen" menu
• Function bar:
  • "Selected source" (e.g. display AUX), "Source", "Treble" and "Bass"

The associated submenus can be called up on the respective display via the following menus:

• "AUX display" menu (e.g. source at the display):
• "Source" menu
  • COMAND (with COMAND controller unit)
  • Display AUX
  • Drive AUX (AUX jack on DVD player)
• "Treble" menu (for adjusting the treble from -10 to +10)
• "Bass" menu (for adjusting the bass from -10 to +10)

If an audio unit is detected or an audio source of the COMAND controller unit, two speaker symbols are shown in the application field and the "AUX" menu item, partitioned as follows, with the relevant menus on each display:

• Application bar:
  • "Disk", "TV", "AUX" and "System"
• Two speaker symbols
• Function bar:
  • "Display AUX" (e.g. selected source), "Source", "Treble" and "Bass"

The associated submenus can be called up on the respective display via the following menus:

• "AUX display" menu (e.g. source at the display):
• "Source" menu
  • COMAND (with COMAND controller unit)
  • Display AUX
  • Drive AUX (AUX jack on DVD player)
• "Treble" menu (for adjusting the treble from -10 to +10)
• "Bass" menu (for adjusting the bass from -10 to +10)

The "AUX" menu item with menus and submenus is selected and operated on the respective display via the following controls on the remote control:

• "Roller":
  • Select respective display
• "4-zone controller with OK":
  • Move in four directions on the interface of each display and select the menus or submenus with "OK"
• "Back":
  • Move back through menu levels
• "Mute":
  • Mute the selected video unit or audio unit for headphones connected by cable
• "VOL +" and "VOL -":
  • Regulate the volume of the selected video unit or audio unit for headphones connected by cable
• "12-key keypad":
  • Alphanumeric input

The video or audio source of the COMAND controller unit is selected and operated via the COMAND controller unit only.

	Electrical function schematic for rear entertainment switch on/off behavior and system settings		PE82.90-P-2052-97FAA
	Electrical function schematic for rear entertainment disk applications		PE82.90-P-2051-97FAA
	Electrical function schematic for rear entertainment AUX applications		PE82.90-P-2050-97FAA
	Overview of system components, telematics		GF82.85-P-9999CE