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Home >> Mercedes Benz >> 2016 >> E400 Base, 2D Convertible >> Repair and Diagnosis >> Electrical >> Motors, Switches, Relays >> Electrical System - Body - 212 Chassis - 2 Of 8 >> Basic Knowledge >> Audio mode, function >> Audio mode, function - GF82.85-P-2030FL

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

MODEL 212 up to 3/1/15 up to model year 2016 

Shown on model 212 as of 1.3.13 

Fig 1: Audio Mode Function Diagram - Shown On Model 212 As Of 1.3.13
G10050561Courtesy of MERCEDES-BENZ USA

Shown on model 212 up to 28.2.13 

Fig 2: Audio Mode Function Diagram - Shown On Model 212 Up To 28.2.13
G10050562Courtesy of MERCEDES-BENZ USA

Function requirements, audio mode, general 

General information on the audio mode 

The audio mode consists of the following component functions:

IMPORTANT MODEL 212 up to 3/1/15

up to model year 2016

with CODE 518 (Media interface)

Further functions are also available and are described in document "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" document.

On vehicles with CODE 867 (SPLITVIEW), the audio equipment forwards the audio signals via the integrated radio interface to the radio frequency headphones or via a direct line to the headphones electrical connector (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 tone settings are shown on the Audio/COMAND display. The tone settings can be adjusted with "Tone" and manufacturer default settings can be restored via the system settings. In vehicles with CODE 810 (Sound system) or CODE 811 (Advanced sound system), as well as 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.

IMPORTANTIMPORTANT With the "AUX" audio source, standard or boost mode can be selected in the "Volume" menu. The input level can be increased by selecting "Boost" mode.

The volume and tone setting 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:

On vehicles with CODE 810 (Sound system) or CODE 811 (Advanced sound system), the audio equipment forwards the desired settings via MOST to the sound system amplifier control unit. On vehicles without CODE 810 (Sound system) or CODE 811 (Advanced sound system), the selected settings are processed internally in the audio equipment. Audio output via the speaker system is interrupted by pressing the mute function button or using the corresponding button on the audio equipment.

Function sequence for volume settings via right multifunction steering wheel button group as of 1.3.13 

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 via right multifunction steering wheel button group up to 28.2.13 

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 sent via the telematics CAN to the audio equipment.

Function sequence for tone settings via remote control (as of 1.3.13 with CODE 867 (SPLITVIEW)) 

By pressing the + and - button, the volume for the audio or video sources is raised or lowered. The user can make the corresponding tone settings by selecting the "Sound" menu via the remote control. The control signals from the remote control are forwarded via infrared directly to the COMAND controller unit and processed there.

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) and - not for all national versions - short wave (SW), long wave (LW)). The following useful signals relevant for the radio reception are modulated onto these signals:

On model 212.0/1, the radio signals for FM 1 and AM are received by the audio equipment via the following route:

On model 212.2, the radio signals for FM 1 and AM are received by the audio equipment via the following route:

The FM 2 radio 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. Demodulation means that the AM tuner integrated in the audio equipment separates the useful signals (audible frequencies) from the carrier signal (not audible).

IMPORTANT MODEL 212 up to 3/1/15

up to model year 2016

with CODE 494 (US version)

MODEL 212 up to 3/1/15

up to model year 2016

with CODE 498 (Japanese version)

Only MW frequencies are received in the AM frequency range.

Function sequence for FM double tuner with multipath reception (FM) 

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 integrates the signals from the FM 1, AM, CL [ZV] and KEYLESS-GO antenna amplifier and from the FM 2 and DAB antenna amplifier to form an optimized signal (phase diversity).

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, provided that the following preconditions are complied with:

Function sequence for radio text+ 

During FM radio operation, additional information about the program can be shown on the Audio/COMAND display using the "Info" menu item.

IMPORTANT MODEL 212 up to 3/1/15

up to model year 2016

with CODE 537 (Digital radio)

The "Info" menu item and additional information are also available for digital radio (DAB).

Function sequence for HD radio mode (with CODE 494 (USA version)) 

The HD radio function is implemented in the COMAND controller unit. The high definition tuner integrated into the COMAND controller unit is a combined AM/FM/weatherband receiver with HD radio function.

The HD tuner that is integrated in the COMAND control unit demodulates the analog AM and FM signals with the two integrated twin tuners and decodes the digital AM and FM signals with the integrated HD radio decoder chips.

The Weatherband function makes it possible to receive US Weatherband signals and the digital carriers of the analog AM/FM programs that are also broadcast by the stations.

The HD radio function improves the audio quality using digital technology:

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

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 following DAB signals:

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:

With a DAB twin tuner, the Digital Audio Broadcasting control unit provides not only the known functions but also the following optimizations and extensions:

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, Satellite Digital Audio Radio (SDAR) (with CODE 536 (SIRIUS satellite radio)) 

The Satellite Digital Audio Radio (SDAR) control unit (as of 1.6.10) or the SDAR/high definition tuner control unit (up to 31.5.10) makes it possible to receive stations from the provider "Sirius Satellite Radio". The SDAR system is controlled through the audio equipment and the control occurs via MOST. The information or displays required for operation are output via the Audio/COMAND display and, if selected, also in 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 from the Sirius satellite radio (Sat 1, Sat 2, terrestrial station) and transmits these signals via a direct line to the relevant SDAR control unit.

The SDAR control unit receives and decodes the signals and transmits them to the audio equipment unit via 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) beneath the front armrest 

External devices (e.g. Universal Serial Bus (USB) stick)) can be connected to the AUX connection electrical connector (except CODE 518 (Media Interface), up to 28.02.13) or the USB electrical connector. On vehicles with the Cockpit Management and Data system (COMAND), the USB electrical connector is installed as of 1.7.11; on vehicles with CODE 510 (Audio 20 with CD changer) or CODE 523 (MB Audio 20 radio), it is installed as of 1.6.12.

The electrical connectors are connected to the audio equipment via direct line. 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, user guidance is provided 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 settings).

IMPORTANT MODEL 212 up to 3/1/15

up to model year 2016

with CODE 518 (Media interface)

The Media Interface electrical connector (X18/70) is installed instead of the AUX connection electrical connector (up to 28.02.13). AUX devices can be connected to the Media Interface electrical connector via the relevant adapter cable. The media interface function is described in a separate document.

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 from a USB memory stick, memory card, CD or DVD can be stored on the hard drive integrated in the audio equipment and then retrieved as required.

IMPORTANT MODEL 212 up to 3/1/15

up to model year 2016

with CODE 498 (Japanese version)

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 

The Bluetooth antenna enables the audio equipment to receive Bluetooth® audio signals from external devices.

As of 1.6.10, Bluetooth® audio is available in the following vehicles:

As of 1.7.11, Bluetooth® audio is also available in the following vehicles:

As of 1.6.12, Bluetooth® audio is also available in the following vehicles:

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.

With Bluetooth® audio these are Audio Video Remote Control Profiles (AVRCP) and Advanced Audio Distribution Profiles (A2DP), and for telephony it is the Hands-free Profile (HFP). 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 telephone)). 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 these devices is found, the audio equipment connects to this device. If this device also supports AVRCP/A2DP, these profiles are also connected.

If a device is connected that only supports HFP and it is changed to the Bluetooth® audio application, "No Bluetooth audio device connected" is shown on the audio equipment if the 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 unit supports AVRCP 1.0, "Audio streaming" is exclusively 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.

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. Audio mode functions can be activated using the remote control. The COMAND controller unit receives the signals from the remote control via the integrated infrared 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 sends the audio signals via an integrated 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 connector.

  Electrical function schematic for Digital Audio Broadcasting function MODEL 212 up to model year 2014 with CODE 537 (Digital radio) PE82.60-P-2057-97DAA
MODEL 212 as of model year 2014 with CODE 537 (Digital radio) PE82.60-P-2057-97DAB
  Electrical function diagram for audio mode function MODEL 212 up to model year 2014 PE82.60-P-2058-97DAA
MODEL 212 as of model year 2014 PE82.60-P-2058-97DAB
  Electrical function schematic for SDAR function MODEL 212 up to model year 2014 with code 536 (SIRIUS satellite radio) PE82.60-P-2060-97DAA
MODEL 212 as of model year 2014 with code 536 (SIRIUS satellite radio) PE82.60-P-2060-97DAB
  Overview of system components, telematics MODEL 212 up to 5/31/12
up to model year 2013		 GF82.85-P-9999FL
MODEL 212 as of 6/1/12 up to 3/1/15
up to model year 2016		 GF82.85-P-9999FLA
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