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Home >> Mercedes Benz >> 2016 >> CLS400 4Matic >> Repair and Diagnosis >> Electrical >> Motors, Switches, Relays >> Electrical System - Body - 218 Chassis - 2 Of 5 >> Basic Knowledge >> Audio mode, function >> Audio mode, function - GF82.85-P-2030FQ

Audio mode, function - GF82.85-P-2030FQ

MODEL 218 up to model year 2015 

Fig 1: Audio Mode Block Diagram - Shown On Model 218
G10083334Courtesy of MERCEDES-BENZ USA

Shown on model 218 as of 01.03.2013 

Fig 2: Audio Mode Block Diagram - Shown On Model 218
G10083335Courtesy of MERCEDES-BENZ USA

Shown on model 218 up to 28.02.2013 

Function requirements, audio mode, general 

General information on the audio mode 

The audio mode consists of the following component functions:

IMPORTANT Further functions of audio mode are described in the information "Media Interface, function".

Audio mode functions are selected using the following controls:

On vehicles except CODE 810 (Sound system) and CODE 811 (Advanced sound system), the audio equipment outputs the audio signals via the vehicle's speaker system. On vehicles with CODE 810 (Sound system) or CODE 811 (Advanced sound system), the audio equipment forwards the audio signals via MOST to the sound system amplifier control unit, which actuates the speaker system.

IMPORTANT More detailed information on the speaker system is available in the "Speaker output function" information.

On vehicles with CODE 867 (SPLITVIEW), the audio equipment forwards the audio signals via the integrated Kleer® radio interface to the radio frequency headphones or via a direct line to the headphones electrical connection (cabled).

Function sequence for volume/tone settings 

All volume and tone settings are performed using the audio equipment. This is performed either by the user or automatically by the audio unit. The volume and sound settings are shown on the audio/COMAND display. The sound settings can be changed with "Tone" and the system returned to the default settings in the system settings menu.

On vehicles with CODE 810 (Sound system) or CODE 811 (Advanced sound system), in addition to the general sound settings (treble, bass and balance) the audio equipment has the additional Logic7 (surround sound) or Surround Sound (Bang&Olufsen) sound setting.

IMPORTANT The tone settings can be carried out separately for each audio source. The volume can be adjusted separately for the traffic information service and navigation announcements.

IMPORTANT With the AUX audio source (over the Media Interface adapter cable (with CODE 518 (Media Interface))) or over the AUX electrical connection (except CODE 518 (Media Interface), up to 28.02.2013) it is possible to select "Standard" or "Boost effect" in the "Volume" menu. The input level can be increased by selecting "Boost effect".

The audio signals are output via the speaker system.

The volume and tone settings partial function is subdivided into the following subfunctions:

Function sequence for manual volume/sound settings 

The manual volume/tone setting function is subdivided into the following subfunctions:

IMPORTANT On vehicles with CODE 810 (Sound system) or CODE 811 (Advanced sound system), the desired settings are forwarded via MOST to the sound system amplifier control unit where they are processed. On vehicles without CODE 810 (Sound system) or CODE 811 (Advanced sound system), the selected settings are processed internally. Audio emitted over the speaker system is interrupted by actuating the Mute button or using the corresponding key on the audio equipment.

Function sequence for volume settings via right multifunction steering wheel button group 

The volume for the audio and video sources is increased or decreased by pressing the + and - buttons, selecting specific functions and volume control.

The control signals are forwarded to the audio equipment via the following route:

Function sequence for volume settings through the audio equipment 

Operating the control on the audio equipment increases or reduces the volume.

Function sequence for sound settings via audio/COMAND control panel 

The user can set the corresponding sound by selecting the "Sound" menu on the audio/COMAND control panel.

The Audio/COMAND control panel control signals are transmitted via the telematics CAN to the audio equipment.

Function sequence for speed-dependent volume control (SDV [GAL]) 

The volume is adapted to the noise level in the vehicle interior using the speed-dependent volume control, which is defined by the vehicle speed. In order to make this adjustment, the instrument cluster transmits vehicle speed information to the audio equipment via the interior CAN.

On vehicles with CODE 810 (Sound system) or CODE 811 (Advanced sound system), the audio equipment forwards the vehicle speed information via MOST to the sound system amplifier control unit.

In accordance with this information the audio equipment or the sound system amplifier control unit raises the output level or lowers it.

On vehicles with CODE 811 (Advanced sound system), the SDV is additionally optimized by using the sound system microphone. The sound system amplifier control unit reads in the signals of the sound system microphone, evaluates the signals, and adjusts the volume of the audio signals to the interior or driving noises.

Function sequence for radio mode (FM/AM) 

The antennas receive signals for the frequency bands FM (ultra-short wave) and AM (medium wave (MW) and (not for all national versions) short wave (SW) as well as long wave (LW)). The following useful signals relevant for the radio reception are modulated onto these signals:

The FM-1 signals are received via direct lines from the audio equipment via the following route:

FM-2 signals are received over direct lines from the audio equipment over the following route:

The AM signals are received via direct lines from the audio equipment via the following route:

The radio mode function sequence consists of the following subfunctions:

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 audio equipment demodulates these signals. In other words, it separates the useful signals (audible frequencies) from the carrier signal (inaudible).

IMPORTANT Only MW frequencies are received in the AM frequency range.

Function sequence for FM twin tuner with multipath reception (FM), except CODE 498 (Japan version) 

For the FM radio frequency band, the useful signals are broadcast using frequency modulation (FM).

The dual FM tuner integrated into the audio equipment demodulates these signals. In other words, it separates the useful signals (audible frequencies) from the carrier signal (inaudible). The audio equipment additionally initiates a reception-dependent changeover between the FM 1, AM, CL and KEYLESS-GO antenna amplifier and the FM 2 and DAB antenna amplifier (model 218.3) or between rear window antenna amplifier 1 and the FM 2, DAB and TV antenna amplifier (model 218.9).

Function sequence for FM twin tuner with multipath reception (FM), with CODE 498 (Japan version) 

The double FM tuner integrated into the audio equipment separates the audio signals (audible frequencies) from the carrier signal (not audible).

The FM 1, AM, CL [ZV] and Keyless-Go antenna amplifier (model 218.3) or the rear window antenna amplifier 1 (model 218.9) is used for Vehicle Information and Communication System (VICS) signals (traffic messages).

The FM 2 and DAB antenna amplifier (model 218.3) or the FM 2, DAB and TV antenna amplifier (model 218.9) is used for FM radio signals.

Reception-dependent switchover is not accomplished.

Function sequence for RDBS (with CODE 494 (USA version)) or RDS (except CODE 494 (USA version), except CODE 498 (Japan version)) 

In addition to the radio program, many radio stations (FM) broadcast additional digital information such as the station name and traffic program identification.

The additional digital information is evaluated by the audio equipment and shown on the Audio/COMAND display if the following preconditions are complied with:

Function sequence for digital radio (DAB) (with CODE 537 (Digital radio (DAB))) 

The Digital Audio Broadcasting control unit allows reception of digital radio in the DAB format. With DAB, the stations are categorized into groups, so-called "Ensembles". Control of the DAB functions is accomplished via the audio equipment. The information or displays required for control are shown on the Audio/COMAND display.

The Digital Audio Broadcasting control unit receives the DAB signals as DAB band III signals via the following route:

The DAB signals are transmitted and made available by the audio unit via MOST.

The audio equipment transmits control and operating signals via MOST to the Digital Audio Broadcasting control unit.

DAB dual tuner 

The Digital Audio Broadcasting control unit is designed as a twin tuner in the following vehicles:

DAB is providing the following optimizations and extensions with the DAB double tuner:

Reception-specific switchover from DAB to FM 

The audio equipment transmits the FM station lists to the Digital Audio Broadcasting control unit. If a comparable FM station is found, it is requested by the Digital Audio Broadcasting control unit. If the DAB reception starts to deteriorate, a switch to the FM station of the audio device occurs.

The reception-dependent switchover from DAB to FM is optimized for "Seamless Linking" in vehicles with DAB twin tuner. The digital audio broadcasting control unit compensates for the time offset between the digital and analog signals so that it is virtually impossible to hear the switchover. This requires that the audio equipment transmit the FM signals to the MOST when the DAB mode is active.

Function sequence for SDAR (with CODE 536 (SIRIUS satellite radio)) 

The satellite digital audio radio (SDAR) control unit permits the reception of stations from the provider "Sirius satellite radio". The SDAR system is controlled through the audio equipment and the control occurs via MOST. The information that is needed for operation and displays is output via the Audio/COMAND display and, if the appropriate setting has been made, also on the instrument cluster. The Sirius satellite radio signal is broadcast 3 times to achieve a diversity of channels (using two satellites and one terrestrial transmitter). The multifunction antenna receives all three channels of the Sirius satellite radio (Sat 1, Sat 2, terrestrial stations) and transmits these signals via a direct line to the Satellite Digital Audio Radio (SDAR) control unit, which decodes the signals and transmits them to the audio equipment via the MOST.

IMPORTANT The Real Time Traffic Data (RTTD) traffic information service is also available through SDAR. Details are given in the function description of the navigation mode.

Function sequence for connections in stowage compartment (telephone compartment) under armrest 

External devices (e.g. Walkman, USB stick) can be connected to the AUX electrical connection (except CODE 518 (Media interface), up to 28.02.2013) and the USB electrical connection.

IMPORTANT On vehicles equipped with the Cockpit Management and Data system (COMAND), the USB electrical connection is installed as of 01.07.2011; on vehicles with CODE 510 (Audio 20 with CD changer) or CODE 523 (MB Audio 20 radio), it is installed as of 01.06.2012.

The electrical connectors are connected to the audio equipment via direct lines. If the "AUX" or "USB storage" menu is activated, the audio equipment outputs the audio data of the connected devices via the speaker system or forwards it via the MOST to the sound system amplifier control unit (with CODE 810 (Sound system) or CODE 811 (Advanced sound system)).

In the "USB storage" menu, the user is guided via the Audio/COMAND display. The audio equipment generates the display information and transmits it to the audio/COMAND display via an LVDS line.

The "Aux" menu is operated from the external device (except the volume and tone settings).

IMPORTANT The Media Interface electrical connection (X18/70) is installed instead of the AUX connection electrical connection.

Function sequence for DVD/CD audio 

The DVD/CD audio and video function can be used to play back audio CDs or audio DVDs (including MP3 format). User guidance for controlling DVD/CD functionality and displaying supplemental information is carried out via the audio/COMAND display.

The data exchange between the audio equipment and the audio/COMAND display takes place via the telematics CAN, but the audio equipment transmits image and video data to the audio/COMAND display via an LVDS line.

Function sequence for Music Register (with CODE 512 (COMAND APS with DVD changer) or with CODE 527 (COMAND APS with single DVD drive (with navigation))) 

Files in MP3 format on a CD/DVD, USB storage device or Secure Digital (SD) card (as of 01.07.2011) can be stored on the hard disk integrated in the audio equipment and then retrieved as required.

IMPORTANT Due to legal regulations, it is not possible to copy MP3 files to the Music Register. Instead of this, in the "Disc" menu one can use "REC" to store music tracks from an audio CD as MP3 file on the COMAND controller unit's hard disk ("rip"). The MP3 files in the Music Register are not imported in this instance, but generated by the audio equipment itself.

Function sequence for Bluetooth® audio (on vehicles up to 31.05.2012 only with CODE 512 (COMAND APS with DVD changer) or CODE 526 (COMAND with single DVD drive (without navigation)) or CODE 527 (COMAND APS with single DVD drive (with navigation)) or CODE 528 (COMAND incl. DVD changer)) 

Bluetooth® audio is available for the following vehicles:

The Bluetooth antenna enables the audio equipment to receive Bluetooth® audio signals from external devices. Bluetooth® audio is divided into the following subfunctions:

Search for devices and authorization 

The same options exist for the authorization of a Bluetooth® audio source as are available for telephony:

The device lists are set up the same for Bluetooth® audio and telephony. In the respective list, only those devices that support the corresponding Bluetooth® profile of the respective function are found or displayed during a search.

The Bluetooth® profiles Audio/Video Remote Control Profile (AVRCP) and Advanced Audio Distribution Profile (A2DP) are needed for Bluetooth® audio and the Hands-Free Profile (HFP) is needed for telephony. If a device supports both functions, it is shown in both lists following authorization.

Connection and reconnection 

An authorized device can be connected by means of selection in the corresponding list. If a device is connected that supports both HFP and AVRCP/A2DP, all profiles are connected. In this case the device is a telephone and the source of Bluetooth® audio at the same time.

On most devices, it is necessary to start the player on the telephone so that it can then be controlled via the audio equipment.

When starting, the audio equipment proceeds with the following strategy: First a check is performed as to whether an authorized telephone is inserted into the mobile phone cradle (with CODE 386 (Comfort telephony)). Where this is the case, the audio equipment connects to the telephone and goes into the comfort telephony status. If no mobile phone cradle is present or no telephone inserted, the audio equipment searches for the last two telephones.

If one of the last two telephones is found, the audio equipment connects itself with this device. If this device also supports AVRCP/A2DP, these profiles are also connected.

If a device is connected that only supports HFP and a change to the Bluetooth® audio application is made, "No Bluetooth audio device connected" is shown on the audio equipment if corresponding audio sources are shown in the device list.

The "Connect last device" function bar enables the last used Bluetooth® audio source to be connected. However, the connection to the current telephone is interrupted here.

If a device is connected that only supports AVRCP/A2DP and a change to the telephone application is then made, the connection to the device is disconnected and the audio equipment begins the search for the last two telephones.

Metadata and display of information 

The display of information for Bluetooth® audio depends on the respective device used. If this device supports AVRCP 1.0, only "Audio streaming" is shown on the Audio/COMAND display and in the instrument cluster.

As of AVRCP 1.3, the track, album and artist are shown. In addition, the currently played time of the track can also be conveyed.

Furthermore, there is the option of changing between the normal track sequence and shuffle.

IMPORTANT It is possible to jump to the next or the previous track using the left multifunction steering wheel button group.

IMPORTANT

Function sequence for audio mode with remote control and headphones (with CODE 867 (SPLITVIEW)) 

Equipment with CODE 867 (SPLITVIEW) enables the driver and the front passenger to use the entertainment and communication systems integrated into the vehicle, including the display on the Audio/COMAND display at the same time and independent of each other. The audio mode functions can be called up via the remote control. The COMAND controller unit receives the signals from the remote control via the integrated Kleer® radio interface.

In order to enable undisturbed concentration on the traffic situation for the driver, the front passenger receives the audio signals via headphones. The COMAND controller unit transmits the audio signals via an integrated Kleer® radio interface to the radio frequency headphones. As an option, external cabled headphones can also be used. The cabled headphones receive the audio signals from the COMAND controller unit via the headphones (cabled) electrical connection.

Electrical function schematic for Digital Audio Broadcasting function   PE82.60-P-2057-97XAA
PE82.60-P-2057-97XAB
Electrical function diagram for audio mode function   PE82.60-P-2058-97XAA
PE82.60-P-2058-97XAB
Electrical function schematic for SDAR function   PE82.60-P-2060-97XAA
PE82.60-P-2060-97XAB
Overview of system components, telematics MODEL 218
as of model year 2013 up to model year 2015		 GF82.85-P-9999FQA 
MODEL 218
up to model year 2013		 GF82.85-P-9999FQ 
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