Component Description For Rear Display Left/Right - GF82.90-P-4020GD

MODEL 204.9 with CODE (864) Rear entertainment system 

Location 

The left rear display is on the rear side of the left front seat head restraint.

The right rear display is on the rear side of the right front seat head restraint.

Both rear displays are identical in design.

The pin assignment (cf. connector A, pin 5) in document "Left/right rear display pin/connector assignment") is used to differentiate between the left and right rear displays. The left rear display is connected to terminal 31.

Task 

The rear display has the following tasks:

• Visualization of user-relevant information 
• Management of connected audio/video units 
• Power and resource management 
• Connection detection 
• Operating interface of rear entertainment system 
• Receive signals 
• Generation of picture signals 
• Generation of infrared (IR) signals 
• Output of audio signals 
• Transmit signals 

Visualization of user-relevant information 

• Graphic displays for user guidance
• Operation
• Display of digital picture signals

Management of connected audio/video units 

The following audio/video devices can be connected to the rear display via the AUX jack:

• Portable DVD player
• Video camera
• MP3 player
• Games console

Power and resource management 

With overvoltage or undervoltage, the active rear display switches off automatically.

Connection detection 

It is necessary to select the AUX source manually. A set of headphones appears as background image. If a video source is recognized the background image disappears and the video signals are displayed.

Operating interface of rear entertainment system 

The rear display forms the interface between the user and the rear entertainment system using the IR interface.

Receive signals 

The signals are received via the following connections:

• Direct lines 
• Telematics CAN (CAN A) 

Direct lines 

The following signals are received via direct lines:

• Analog audio signals from the DVD player (A40/4) via the stereo line
• Analog picture signals from the DVD player via the Y brightness (luminance)/C color information (chrominance) (Y/C) line
• Analog picture and video signals from the external audio or video unit connected via the AUX jack
• Control signals from the remote control via the IR interface

Telematics CAN 

The rear display is a station on the telematics CAN and communicates with the following components:

• Audio unit
• DVD player

Generation of picture signals 

The rear display generates digital picture signals from the received analog picture signals for display on the screen.

Generation of IR signals 

The rear display generates digital IR audio signals from the received analog audio signals for transmission to the connected headphones (cordless).

Output of audio signals 

The rear display provides the following output possibilities for audio signals:

• Analog: Headphones connected to the rear display by means of a cable
• Digital (IR): Headphones (cordless)

The volume of audio output over the headphones connected to the rear display by means of a cable can be adjusted using the remote control.

The volume of audio output over the headphones (cordless) can be adjusted using the volume control on the headphones (cordless).

Transmit signals 

The signals are transmitted via the following connections:

• Direct lines 
• Telematics CAN 

Direct lines 

The following signals are sent via direct lines:

• Analog audio signals to the headphones connected to the rear display by means of a cable
• Digital audio signals (IR) to the IR headphones (cordless) via the IR interface

Telematics CAN 

The rear display is a station on the telematics CAN and communicates with the following components:

• Audio unit
• DVD player
  Fig 2: Identifying Left Rear Display

  Courtesy of MERCEDES-BENZ USA

Design 

An audio amplifier for the integrated headphones socket (3.5 mm) is also integrated into the left rear display.

The left rear display has the following features:

• 8 TFT color display
• Display format 16:9
• Maximum resolution: 800 X 480 pixels
• Color depth: 3 X 6 bit (262, 144 colors can be displayed)

Technical data Designation	Unit	Values	Tolerance range	Remarks
Left rear display (A40/5) and right rear display (A40/6)
Power supply	VV	12		Operating voltage (U BNom )
Voltage limits	VV	6		Minimum (UBmin )
	VV	9		Minimum (UBmin ) (for background illumination)
	VV	16		Maximum (UBmax )
Power consumption		Tbd		Standby
	A	1		Action
		Tbd		Additional action
	μA	100		Quiescent current (maximum) (I 0 )
Reverse polarity protection				The inputs and outputs are protected against polarity reversal.
Additional specific parameters	CD	450		Light intensity (typical)
Flash capability/coding capability				YES/YES

Wiring diagram for DVD player control unit

PE82.60-P-2104-97FAA