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Home >> Mercedes Benz >> 2009 >> E 320 BLUETEC (211.022) V6-3.0L DSL Turbo (642.920) >> Repair and Diagnosis >> Accessories and Optional Equipment >> Radio, Stereo, and Compact Disc >> Description and Operation >> GF82.85-P-2030TXB Audio Mode, Function

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



GF82.85-P-2030TXB Audio Mode, Function
- with CODE (527) COMAND APS with single DVD drive (with navigation)
- except CODE (498) Japan version
- except CODE (494) USA version


General information
The audio mode is made up of the following functions which can be activated using the Audio menu item:
^ Radio mode (ultra-short wave (FM), medium wave (MW), long wave (LW), short wave band (SW))
^ Media player (Compact Disk (CD), Digital Versatile Disk (DVD), Secure Digital (SD) card)
^ Music Register (hard disk)

A further function is described in a separate document:
^ Digital Audio Broadcasting (DAB) function, with code 537 Digital radio and with code 833 Great Britain version

Operating instructions
Audio functions are operated using the following components:
^ Left multifunction steering wheel button group (S110)
^ Right multifunction steering wheel button group (S111)
^ Control panels of the COMAND operating, display and controller unit (A40/3)
^ Voice control system

Function requirements
^ Status "Circuit 30 ON"
^ The COMAND operating, display and controller unit works correctly
^ No fault in antenna system (radio function)
^ The medium to be played is available and correct

Function sequence for radio mode (FM/MW/LW/SW), in general
The antennas in the rear window (model 211.0, 219) or in the side windows (model 211.2) receive high frequency (HF) signals for the radio-frequency bands frequency modulation (FM) and amplitude modulation (AM) (MW, LW, SW). The following useful signals relevant for the radio reception are modulated onto these HF signals:
- Music signals
- Speech signals
- Data signals (e.g. Traffic Message Channel (TMC) messages (traffic information))

The high frequency signals are routed via direct lines to the corresponding antenna amplifier. These antenna amplifiers filter the frequencies of the radio frequency bands out of the received HF signals and amplify them. The amplified signals are then sent over coaxial lines (FM, AM) to the tuner integrated into the COMAND operating, display and controller unit where they are demodulated.

The demodulated audio signals in vehicles with code (810) Sound system are routed from the COMAND operating, display and controller unit via the Media Oriented System Transport (MOST) to the sound system amplifier (N40/3) where they undergo final amplification.The audio is then output by the following speakers via direct lines:
- Left front door speaker group (H4/1)
- Right front door speaker group (H4/2)
- Left rear door speaker group (H4/3)
- Right rear door speaker group (H4/4)
- Bass box speaker (H4/17)
- Center cockpit speaker (centerfill) (H4/27)
- Left rear surround speaker (H4/54)
- Right rear surround speaker (H4/57)

The audio signal for the bass box speaker travels from the COMAND operating, display and controller unit via MOST to the amplifier for sound system and from there, over direct lines via the subwoofer amplifier (N40/9) to the bass box speaker.

For vehicles except code 810 Sound system, the audio signals undergo final amplification by the COMAND operating, display and controller unit and are then output over the following speakers via direct lines:
- Left front door speaker group
- Right front door speaker group
- Left rear door speaker group
- Right rear door speaker group
- Center cockpit speaker (centerfill)

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

FM double tuner function sequence with phase diversity (FM)
For the FM radio frequency band, the useful signals are broadcast using frequency modulation (FM). The FM double tuner integrated into the COMAND operating, display and controller unit demodulates these signals. In other words, it also separates the useful signals (audible frequencies) from the carrier signal (inaudible).
The COMAND operating, display and controller unit also performs changeover depending on the reception quality.

Function requirements for Radio Data System (RDS)
^ An RDS station is tuned
^ The "RDS" function is activated

Function sequence for RDS
Apart from the normal radio program, many radio stations (FM) transmit additional digital information such as station names, program type (PTY) (e.g. pop, culture, etc.) and traffic program identification. This information is evaluated by the COMAND operating, display and controller unit and appears on the display of the COMAND operating, display and controller unit:

Function sequence for media player
A DVD drive is integrated into the COMAND operating, display and controller unit. This enables audio CDs or audio DVDs (including in MPEG-1 audio layer 3 (MP3) format) to be played. The integrated SD card reader enables music files in MP3 or Windows Media Audio (WMA) formats to be played or copied into the MUSIC REGISTER.

User navigation for controlling DVD/CD functionality and displaying supplemental information is carried out via the display of the COMAND operating, display and controller unit. On vehicles with code 810 Sound system, data exchange takes place between the COMAND controller unit and sound system amplifier over MOST. The audio output takes place over the following speakers:
- Left front door speaker group
- Right front door speaker group
- Left rear door speaker group
- Right rear door speaker group
- Bass box speaker
- Center cockpit speaker (centerfill)
- Left rear surround speaker
- Right rear surround speaker

The audio signal for the bass box speaker travels from the COMAND operating, display and controller unit via MOST to the amplifier for sound system and from there, over direct lines via the subwoofer amplifier to the bass box speaker.

In vehicles except code 810 Sound system, the audio output takes place using direct lines via the COMAND operating, display and controller unit and through the following speakers:
- Left front door speaker group
- Right front door speaker group
- Left rear door speaker group
- Right rear door speaker group
- Center cockpit speaker (centerfill)

The DVD/CD menu and title menu stored on the inserted DVD/CD appear on the display of the COMAND operating, display and controller unit. For this reason, the function scope and menu display are dependent on each respective medium. In the event that one of the two menus is missing on the DVD/CD, the display of the COMAND operating, display and controller unit provides the corresponding menu item with a gray background.

General Music Register, with code 527 COMAND APS with single DVD drive (with navigation)
The integrated hard drive in the COMAND controller unit enables files (in MP3 format) to be stored from the CD over the SD interface and then called up as desired.





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