TV-Mode, Function - GF82.85-P-2011RFN

Model 253 (except 253.99) 

as of model year 2020 

with code 865 (digital TV) 

Courtesy of MERCEDES-BENZ USA

Function requirements, general 

• Circuit 30t ON
• Transport mode not active
• No smartphone connected via Android Auto or CarPlay

TV mode 

The TV tuner is integrated into the head unit and enables the reception of digital television programs. TV images are shown on the Audio/COMAND display.

At a vehicle speed of more than 6 km/h, TV pictures are no longer shown on the Audio/COMAND display.

The head unit can be switched on using the "ON" button in the respective lower control panel. The respective lower control panel sends the status of the "ON" button over the LCP-LIN, touchpad and the telematics CAN to the head unit.

The following TV standards can be received and processed:

• DVB-T1/DVB-T2 (H.264, H.265, HEVC) (Digital Video Broadcasting - Terrestrial)

  (Not for vehicles with code 498 (Japan version), or code 835 (Additional parts for South Korea vehicles))

• ISDB-T (Integrated Services Digital Broadcasting - Terrestrial)

  (For vehicles with code 498 (Japan version))

• HD-DMB/DMB (digital media broadcast)

  (For vehicles with code 835 (Additional parts for South Korea vehicles))

The TV functions can be operated using the following controls:

• Multifunction steering wheel button group 

  The TV functions can be operated using the head unit multifunction steering wheel button group. The volume can be adjusted with the volume adjustment switch in the head unit multifunction steering wheel button group.

  The steering wheel electronics reads the control signals directly. The steering wheel electronics send the control signals over the steering wheel CAN to the steering column tube module control unit and from there over the suspension FlexRay, electronic ignition lock control unit and the user interface CAN to the head unit.

• Touchpad 

  The touchpad can be used to operate the tv functions. The touchpad sends the operation signals over the telematics CAN to the head unit.

• Audio/COMAND display 

  The Audio/COMAND display detects swipe movements and touch movements on the display and transmits the operation signals to the head unit via the telematics CAN.

• Upper control panel control unit, lower control panel 

  The TV functions can be activated on the upper control panel control unit. The volume ca be regulated using the volume adjustment button (manual transmission) on the left lower control panel or using the volume control button (automatic transmission) on the right lower control panel. The upper control panel control unit sends the operation signals, the left lower control panel sends the status of the volume adjustment button (manual transmission), and the right lower control panel sends the status of the volume control button (automatic transmission) over the LCP-LIN, touchpad and the telematics CAN to the head unit.

The TV tuner control unit splits up the video and audio signals that are contained in the TV signals.

The TV mode function comprises the following subfunctions:

• Receipt of TV signals 
• Output of video signals 
• Audio signal output 
• Special features of DVB-T/DTV-T2 
• Special features of ISDB-T 
• Special features of HD-DMB 

Receipt of TV signals 

TV 1 signals are received by the rear window antenna A2/32 (model 253.3), or the windshield A2/118 antenna (model 253.9), and forwarded to the head unit over the TV 1 and DAB band III antenna amplifier.

TV 2 signals are received by the rear window antenna A2/32 and forwarded over the FM2, DAB and TV2 antenna amplifier to the head unit.

TV 3 signals are received by the windshield antenna and forwarded to the head unit over the TV 3 antenna amplifier.

The head unit processes the TV signals and separates the video signals from the audio signals.

Operating electrical or electronic devices (e.g. USB chargers) inside the vehicle can significantly impair the reception quality.

Output of video signals 

The head unit sends the video signals over an HSVL line to the Audio/COMAND display.

Audio signal output 

The head unit amplifies the audio signals and, on vehicles except code 810 (Sound system), they are output at the speaker system.

On vehicles with code 810 (Sound system), the head unit sends the audio signals over MOST to the sound system amplifier control unit, which amplifies the audio signals and outputs them at the speaker system.

Special features of DVB-T/DTV-T2 

The TV tuner integrated into the head unit supports the following video compression standards:

• MPEG-2
• MPEG-4 AVC (H.264)
• MPEG-H (H.265)

Encrypted programs can be received with the Common Interface Plus (CI+) module that is integrated into the TV card reader. The TV card reader is installed in the glove compartment and connected to the head unit through a direct line.

High-definition, encrypted pay-TV programs can be received.

The TV tuner supports video text with Latin ASCII character sets (so currently, for example, no Greek or Cyrillic character sets).

Special features of ISDB-T 

The TV tuner integrated into the head unit supports video text through the Broadcast Markup Language (BML), and Electronic Program Guide (EPG).

The following ISDB-T sub-standards are supported:

• "one-segment" (1seg) (low-resolution signal for mobile reception at low bandwidth)
• "full-segment" (high-resolution signal for reception at high bandwidth)

Special features of HD-DMB 

The TV tuner integrated into the head unit supports high-definition television. A device-specific CAS ID can be shown on the Audio/COMAND display. Using this CAS ID, fee-based additional services can be enabled by the program provider.

	Electrical function diagram for TV mode, function		PE82.85-P-2065-97FBC
	Overview of system components, telematics		GF82.85-P-9999RFM