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Audio Mode, Function - Gf82.85-P-2030CE

MODEL 204.0/2 as of model year 2009 

MODEL 204.3/9 

Fig 1: Audio Mode - Block Diagram
G10084753Courtesy of MERCEDES-BENZ USA

Function requirements, audio mode, general 

IMPORTANT Audio mode functions are selected using the following controls:

General information on the audio mode 

Audio mode functions are selected using the following controls:

The control signals of the left multifunction steering wheel button group and right multifunction steering wheel button group are forwarded to the audio equipment in the following way:

The control signals of the Audio/COMAND control panel are forwarded over the telematics CAN to the audio equipment, on model 204.0/2/3 with CODE 255 (AMG Performance Media) over the AMG Performance Media control unit.

The signals from the buttons on the audio equipment are processed internally in the audio equipment.

The voice command from the VCS (with CODE 511 (Audio 50 APS with DVD changer), with CODE 525 (MB Audio 50 APS radio), with CODE 512 (COMAND APS with DVD changer) or with CODE 527 (COMAND APS with single DVD drive (with navigation))) are forwarded by the hands-free system microphone to the audio equipment where they are processed.

The control signals from the remote control (model 204.9 with CODE 867 (SPLITVIEW)) are forwarded via infrared directly to the COMAND controller unit where they are processed.

Control and information displays are generated by the audio equipment, and shown over a low voltage differential signaling line on the Audio/COMAND display, on model 204.0/2/3 with CODE 255 (AMG Performance Media) over the AMG Performance Media control unit.

The audio mode consists of the following component functions:

Function sequence for volume and sound 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.

IMPORTANT The "Volume" menu allows selection of the settings "Standard" or "Boost effect" for the AUX audio source (through the Media interface adapter cable (with CODE 518 (Media interface)) or the AUX electrical connector, up to 31.05.2013). The input level can be increased by selecting "Boost effect".

On vehicles with CODE 810 (Sound system), the audio equipment has an additional Logic 7 tone setting (surround sound).

IMPORTANT The sound settings can be set separately for each audio and video source. The volume can be adjusted separately for the traffic information service and navigation announcements.

The audio signals are output via the speaker system.

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

Function sequence for manual volume and sound settings 

The manual volume and sound settings are subdivided into the following subfunctions:

IMPORTANT The selected settings are relayed on vehicles with CODE 810 (Sound system) over MOST to the sound system amplifier control unit where they are processed. On vehicles except code 810 (Sound system), the settings are processed by the audio equipment. Audio emitted through the speaker system is interrupted by actuating the Mute button (S111s6) or using the corresponding key on the audio equipment.

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

Pressing the + and - button for setting specific functions and volume control (S111s1) enables the volume for audio and video source to be increased or reduced.

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 enables the volume to be raised or lowered for the audio or video sources.

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 control signals of the Audio/COMAND control panel are forwarded over the telematics CAN to the audio equipment, on model 204.0/2/3 with CODE 255 (AMG Performance Media) over the AMG Performance Media control unit.

IMPORTANT With CODE 510 (Audio 20 with CD changer) or with CODE 523 (MB Audio 20 radio), the "Tone" menu can also be activated on the audio equipment. Settings are performed with the audio/COMAND control panel.

Function sequence for volume and tone settings over remote control (model 204.9 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 with the aid of the speed-dependent volume control defined by the vehicle speed. To do this, the instrument cluster transmits information on vehicle speed via the interior CAN to the audio equipment (without CODE 810 (Sound system)) or over MOST to the sound system amplifier control unit (with CODE 810 (Sound system)).

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

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:

The FM and AM signals are received over direct lines from the audio unit in the following manner:

AM signals:

FM-1 signals:

FM-2 signals:

The radio mode function sequence consists of the following subfunctions:

IMPORTANT The function sequence for receiving traffic data for vehicles with CODE 498 (Japan version) (over the Vehicle Information and Communication System (VICS)) is described in the document "Navigation mode, function".

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. This means that the AM tuner integrated into the audio equipment separates the audio signals (audible frequencies) from the carrier signal (not audible).

IMPORTANT In vehicles with CODE 498 (Japan version) or CODE (494) USA version, only MW frequencies can be 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 also provides for reception-dependent switchover between the antenna amplifiers for the FM-1- and FM-2-signal.

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 following are used for Vehicle Information and Communication System (VICS) signals (traffic messages):

The following are used for FM radio signals:

Reception-dependent switchover is not accomplished.

Function sequence for Radio Broadcast Data system (RBDS) (with CODE 494 (USA version)) or Radio Data System (RDS) (except CODE 494 (USA version), except CODE 498 (Japan version)) 

In addition to the radio program, many radio stations (FM) also transmit additional digital information.

The additional digital information (e.g. station name and radio traffic information) is evaluated by the audio equipment and shown on the Audio/COMAND display if the following preconditions are met:

Function sequence for high-definition (HD) radio mode (as of 01.06.2010 up to 30.11.2014 with CODE 494 (USA version) and CODE 512 (COMAND APS with DVD changer), CODE 528 (COMAND incl. DVD changer) or as of 01.12.2014 with CODE 494 (USA version) and CODE 527 (COMAND APS with single DVD drive (with navigation))) 

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

The HD radio function is implemented in the COMAND controller unit. The integrated (HD) tuner is a combined AM/FM/Weatherband (WB) receiver with HD radio function. The (HD) tuner in the COMAND controller unit demodulates the analog AM and FM signals with the two integrated double tuners and decodes the digital AM And FM signals with the integrated HD radio decoder chips. The weatherband feature allows reception of US weatherband signals. The HD radio function also allows additional reception of digital carrier waves for analog AM/FM programs, which are also broadcast by the stations. The stations also broadcast other audio channels and data with the digital carriers. This supplements the program with up to two audio channels per frequency (e.g. foreign language program from National Public Radio (NPR)) and supplemental information (e.g. title, artist).

Additional transmission of digital carriers is designated as "On Channel", the digital station is tuned to the same frequency as the analog station. The digital transmission process in the FM and AM band is known as "in-band". In contrast to the satellite digital audio radio (satellite radio) (SDAR) function (with CODE 536 (SIRIUS satellite radio)), regional stations and programs are received by the HD radio function and no fees will be charged.

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

The Digital Audio Broadcasting control unit permits the reception of stations in the Digital Audio Broadcasting (Digital Radio) (DAB) format. The stations are categorized into groups in DAB, 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 DAB band III signals are used for large area broadcasting and contain mostly stations with a large range or national stations. The DAB L band signals are used for local broadcasts and contain mostly conurbation stations.

IMPORTANT In vehicles as of 01.12.2010, only DAB band III signals are processed and the multifunction antenna is not longer required for DAB.

The DAB-L-Band signals (up to 30.11.2010) are received by the Digital Audio Broadcasting control unit over direct lines by the multifunction antenna.

The Digital Audio Broadcasting control unit receives the DAB Band III signals over direct lines in the following way:

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

Reception-dependent switchover of DAB to FM (as of 01.06.2009) 

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 the system switches over to the FM station being received by the audio equipment.

On model 204.0/2 as of 01.03.2011, model 204.3 and on model 204.9 as of 01.06.2012, the reception-specific switchover from DAB to FM is optimized through "Seamless Linking". 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 send the FM signals to the MOST when the DAB mode is active.

DAB twin tuner (model 204.0/2 as of 01.03.2011, model 204.3, model 204.9 as of 01.06.2012) 

The Digital Audio Broadcasting control unit is designed as a twin tuner and provides not only the known functions, but also the following optimizations and extensions:

Function sequence for Satellite Digital Audio Radio (satellite radio) (SDAR) (with CODE 536 (SIRIUS satellite radio)) 

The corresponding SDAR control unit enables "Sirius Satellite Radio" provider channels to be received. The SDAR system is controlled through the audio equipment and the control occurs over MOST. The information or displays required for control are output via the Audio/COMAND display and 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 station). The multifunction antenna receives all three channels (Sat 1, Sat 2, terrestrial station) and sends these signals via a direct line to the corresponding SDAR control unit. The SDAR control unit receives and decodes the signals and transmits them to the audio equipment unit via MOST.

IMPORTANT On vehicles as of 01.06.2010 (on vehicles with CODE 512 (COMAND APS with DVD changer) already as of 01.06.2009), the Real Time Traffic Data service (RTTD) is also available via SDAR. Details are given in the function description of the navigation mode.

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 and the display of additional information are carried out on the Audio/COMAND display. Data exchange between the audio unit and the Audio/COMAND display takes place via the telematics CAN.

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

The hard disk integrated into the audio unit enables files in MP3 format to be stored from CD/DVD, USB memory stick or a Secure Digital (SD) card and then called as required.

IMPORTANT On vehicles with CODE 498 (Japan version), MP3 files may not be copied to the Music Register due to legal specifications. 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 (model 204.0/2 as of 01.03.2011, model 204.3, model 204.9 as of 01.06.2012) 

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. 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. That means that the device is now a telephone and at the same time a source for Bluetooth® audio. 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 according to the following strategy: First a check is performed as to whether an authorized telephone is inserted into the mobile phone cradle (accessories, with CODE 386 (Mobile phone)).

Where this is the case, the audio equipment connects to the telephone and goes into the comfort telephony status. If a mobile phone cradle is present, however, phone not plugged in, an inquiry is displayed after 2 minutes whether the system is to switchover to basic telephony. If answered with "No" the system remains in 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 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.

If a change is made when in the comfort telephony status to the Bluetooth® Audio application, the audio equipment also shows "Bluetooth audio device not connected", insofar as the corresponding audio sources are included 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.

IMPORTANT The search process with "Connect last device" can only be interrupted by changing to telephony. Otherwise, the search is continued in the background.

When corresponding audio sources are not present in the device list, "No Bluetooth audio device authorized" is displayed and the selection possibility "Connect last device" is suppressed.

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 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.

IMPORTANT

Function sequence for audio mode with remote control and headphones (model 204.9 with CODE 867 (SPLITVIEW) 

Equipment with CODE 867 (SPLITVIEW) in model 204.9 enables the driver and the front passenger to use the entertainment and communication systems integrated into the vehicle including the ability to display them on the Audio/COMAND display at the same time and independently 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 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 over 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 connector.

  Electrical function schematic for Digital Audio Broadcasting function Model 204.0/2 as of model year 2012, model 204.3, model 204.9 as of model year 2013, with code (537) Digital radio PE82.60-P-2057-97FAB
Model 204.0/2 as of model year 2009 up to model year 2012, model 204.9 as of model year 2010 up to model year 2013, with code (537) Digital radio PE82.60-P-2057-97FAA
  Electrical function diagram for audio mode, function Model 204.0/2 as of model year 2012, model 204.3, model 204.9 as of model year 2013 PE82.60-P-2058-97FAB
Model 204.0/2 up to model year 2012, model 204.9 up to model year 2013 PE82.60-P-2058-97FAA
  Electrical function schematic for SDAR function Model 204.0 as of model year 2012, model 204.3, model 204.9 as of model year 2013, with code (536) SIRIUS satellite radio PE82.60-P-2060-97FAB
Model 204.0 up to model year 2012, model 204.9 up to model year 2013, with code (536) SIRIUS satellite radio PE82.60-P-2060-97FAA
  Overview of system components, telematics   GF82.85-P-9999CE 
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