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Home >> Mercedes Benz Truck >> 2009 >> R 350 4MATIC (251.165) V6-3.5L (272.967) >> Repair and Diagnosis >> Accessories and Optional Equipment >> Radio, Stereo, and Compact Disc >> Description and Operation >> GF82.85-P-2030GQE Audio Mode, Function

GF82.85-P-2030GQE Audio Mode, Function



GF82.85-P-2030GQE Audio Mode, Function
- with CODE (510) Audio 20 with CD changer


Function requirements
^ Status circuit 30 On or circuit 15R On
^ The radio is authorized and in perfect working order
^ No fault in antenna system (radio function)
^ Audio-CD is inserted (for disk operation)
^ A Radio Data System (RDS) station is set and the RDS function activated
^ The radio station also transmits additional digital information

General audio mode function sequence
The audio mode function consists of the following function sequences:
^ Radio mode function sequence (AM/FM)
^ Disk function sequence

Further subfunctions are described in separate documents:
^ Digital Audio Broadcasting control unit (DAB) (with code (537) Digital radio)
^ Media interface (with code (518) Media interface)

Operating instructions
Control, selection or adjustment of the audio functions is possible with the following components
- Left multifunction steering wheel button group (S110) or right multifunction steering wheel button group (S111)
- Control buttons on radio (A2)

Radio mode function sequence (AM/FM)
The function sequence is subdivided into the following subfunctions:
^ Radio mode function sequence (AM/FM)
^ AM tuner function sequence (MW/LW/SW)
^ FM tuner with phase diversity function sequence (FM/ Traffic Message Channel (TMC))
^ Radio Data System (RDS) function sequence

Radio mode function sequence (AM/FM)
The rear window antennas or the FM/AM/RRCL [FZV] antenna (A2/93a1) in the roof antenna module (A2/93) receive high frequency (HF) signals for the FM and AM (MW, LW, SW) radio frequency bands. The following useful signals relevant for the radio reception are modulated onto these HF signals:
- Music signals
- Speech signals
- Data signals (e.g. TMC messages (traffic information))

These HF signals from the rear window antennas are forwarded via direct lines to the FM rear window antenna amplifier (A2/19) and from there to the roof antenna module. These two amplifiers filter the frequencies of the radio frequency bands out of the received HF signals and amplify them. The amplified signals are then sent from the roof antenna module via coaxial lines (FM, AM) to the tuner integrated in the radio where they are demodulated.

The demodulated audio signals on vehicles with code (810) Sound system are transferred by the radio over the Media Oriented System Transport (MOST) to the sound system amplifier (N40/3) and amplified.
The audio is then output by the following speakers via direct lines:
- Left front door speaker (H4/5)
- Right front door speaker (H4/6)
- Left rear door speaker (H4/3)
- Right rear door speaker (H4/4)
- Center cockpit speaker (centerfill) (H4/27)
- Subwoofer speaker (H4/29)
- Left front door tweeter (H4/33)
- Right front door tweeter (H4/34)
- Left rear door tweeter (H4/35)
- Right rear door tweeter (H4/36)
- Left rear surround speaker (H4/54)
- Right rear surround speaker (H4/57)

The audio signal for the subwoofer speaker travels via MOST from the radio to the sound system amplifier and from there, over the subwoofer amplifier (N40/9), via discrete lines, to the Subwoofer speaker.

In vehicles without code (810) Sound system, the audio is output by the radio by means of direct lines over the following speakers:
- Left front door speaker
- Right front door speaker
- Left rear door speaker
- Right rear door speaker
- Left front door tweeter
- Right front door tweeter
- Left rear door tweeter
- Right rear door tweeter

AM tuner function sequence (MW/LW/SW)
For the MW, LW and SW radio frequency bands, the useful signals are broadcast using amplitude modulation (AM). The AM tuner integrated into the radio demodulates these signals. In other words, it separates the useful signals (audible frequencies) from the carrier signal (inaudible).

FM tuner with phase diversity function sequence (FM/TMC)
For the FM radio frequency band, the useful signals are broadcast using frequency modulation (FM). The FM tuner integrated into the radio demodulates these signals. In other words, it also separates the useful signals (audible frequencies) from the carrier signal (inaudible). The radio also enables an additional reception-specific changeover between the two antenna amplifiers. This function runs automatically.

RDS function requirements
^ An RDS station is tuned in.
^ The "RDS" function is activated

Function sequence for RDS
Apart from the normal radio program, many radio stations transmit additional digital information such as station name, program type (e.g. pop, culture, etc.) and traffic program identification. The additional digital information is evaluated and displayed by the radio.

Disk function sequence
The disc function sequence comprises the following subfunction sequences:
^ CD function sequence or MP3
^ AUX function sequence (without code (518) Media interface)

CD function sequence or MP3
A 6-disk CD changer is integrated into the radio. The CD changer is used to read in the audio CDs (including in MP3 format) and they are internally processed by the radio. The user guidance for control of the CD functions (e.g. track selection) and for showing supplemental information (e.g. title) is accomplished on the radio display.

The occupied CD slots are indicated on the radio display. CD slots "1" to "6" are numbered consecutively. The CD menu and title menu, which are also shown on the radio display, are stored on the inserted CD. This is why the functional scope and menu display are dependent on the actual CD inserted.

In vehicles with code (810) Sound system, the radio routes the audio signals via the MOST to the sound system amplifier, where they undergo final amplification.

The audio output is then sent from the sound system amplifier to the following speakers via direct lines:
- Left front door speaker
- Right front door speaker
- Left rear door speaker
- Right rear door speaker
- Center cockpit speaker (centerfill)
- Subwoofer speaker
- Left front door tweeter
- Right front door tweeter
- Left rear door tweeter
- Right rear door tweeter
- Left rear surround speaker
- Right rear surround speaker

The audio signal for the subwoofer speaker travels via MOST from the radio to the sound system amplifier and from there, over the subwoofer amplifier, via discrete lines, to the subwoofer speaker.

In vehicles without code (810) Sound system, the audio is output by the radio by means of direct lines over the following speakers:
- Left front door speaker
- Right front door speaker
- Left rear door speaker
- Right rear door speaker
- Left front door tweeter
- Right front door tweeter
- Left rear door tweeter
- Right rear door tweeter

AUX function sequence (without code (518) Media interface)
If an external device (e.g. MP3 player) is connected via the AUX jack and the "AUX" menu item is called up, the base screen is displayed. The following appears on the display of the radio:
- Status line
- No display

- Field of application
- No display, 2 speaker symbols only

- Function line
- "AUX" and "Tone"

The associated submenus can be called up on the radio display in the following menu items:
- "AUX" menu item
- No other submenus

- "Tone" menu item
- "Treble"
- "Bass"
- "Balance/fader"
- "Surround sound" (with code (810) Sound system)

The menu navigation and display of the connection options are shown on the display of the radio and are dependent on the respective portable terminal connected.

In vehicles with code (810) Sound system, the radio routes the audio signals via the MOST to the sound system amplifier, where they undergo final amplification.

The audio output is then sent from the sound system amplifier to the following speakers via direct lines:
- Left front door speaker
- Right front door speaker
- Left rear door speaker
- Right rear door speaker
- Center cockpit speaker (centerfill)
- Subwoofer speaker
- Left front door tweeter
- Right front door tweeter
- Left rear door tweeter
- Right rear door tweeter
- Left rear surround speaker
- Right rear surround speaker

The audio signal for the subwoofer speaker travels via MOST from the radio to the sound system amplifier and from there, over the subwoofer amplifier, via discrete lines, to the subwoofer speaker..

In vehicles without code (810) Sound system, the audio is output by the radio by means of direct lines over the following speakers:
- Left front door speaker
- Right front door speaker
- Left rear door speaker
- Right rear door speaker
- Left front door tweeter
- Right front door tweeter
- Left rear door tweeter
- Right rear door tweeter





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