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

Model 205 

as of model year 2019 

Model 253.99 

G13025026Courtesy of MERCEDES-BENZ USA

Shown on model 205.0/1/2/3, 253.99 

G13025027Courtesy of MERCEDES-BENZ USA

Shown: model 205.4 

IMPORTANT

Model 205 as of model year 2019

with code 446 (Touchpad only)

Model 205

as of model year 2019

with code 448 (Touchpad)

Model 253.99

with code 446 (Touchpad only)

Information on touchpad 

The touchpad is installed in two variants.

Variant 1 (with code 448 (Touchpad)): The touchpad is installed together with the Audio/COMAND control panel (A40/9). The touchpad is connected only to the telematics CAN (CAN A).

Variant 2 (with code 446 (Touchpad only)): The touchpad is installed instead of the Audio/COMAND control panel. In this case, the upper control panel control unit, the left lower control panel and right lower control panel are connected to the touchpad via UBF-LIN. The touchpad is also connected to the telematics CAN.

Function requirements, general 

General information on the audio mode 

The head unit is switched on or off via the "ON" button on the left lower control panel (manual transmission) or on the right lower control panel (automatic transmission). The volume can be adjusted via the volume control button (manual transmission) on the left lower control panel, via the volume adjustment button (automatic transmission) on the right lower control panel or via the volume control switch in the head unit multifunction steering wheel button group.

The left lower control panel transmits the status of the "ON" button and of the volume control button (manual transmission) or the right lower control panel transmits the status of the "ON" button and of the volume adjustment button (automatic transmission) via the LCP LIN, the Audio/COMAND control panel (except code 446 (Touchpad only)) or the touchpad (with code 446 (Touchpad only)) and the telematics CAN to the head unit.

The menu for radio reception or for the media sources can be called up using the buttons on the upper control panel control unit.

The upper control panel control unit transmits operation signals via the LCP LIN, the Audio/COMAND control panel (except code 446 (Touchpad only)) or the touchpad (with code 446 (Touchpad only)) and the telematics CAN to the head unit.

The menu contents are generated by the head unit and shown on the Audio/COMAND display. The head unit transmits an ON signal to the Audio/COMAND via the telematics CAN. The head unit transmits the image data to the Audio/COMAND via the HSVL line.

The audio mode functions can be selected, activated and adjusted with the Audio/COMAND controller on the Audio/COMAND control panel (except code 446 (Touchpad only)). The "Back" button supports navigation in the menus. The Audio/COMAND control panel sends the control signals via telematics CAN to the head unit.

The audio mode functions can be operated with the touchpad (with code 448 (Touchpad) or with code 446 (Touchpad only)). The touchpad sends the operation signals over the telematics CAN to the head unit.

The audio mode functions can be selected, activated and regulated with the head unit multifunction steering wheel button group. The volume can be adjusted using the head unit multifunction steering wheel button group volume adjustment switch. The steering wheel electronics reads in the control signals of the head unit multifunction steering wheel button group directly. The steering wheel electronics send the control signals over the steering wheel CAN to the steering column tube module control unit and from there over the suspension FlexRay, electronic ignition lock control unit and the user interface CAN to the head unit.

In vehicles with CODE 531 (COMAND APS), the audio mode functions can be operated with the voice control system. The voice commands are converted into electric signals by the driver hands-free system microphone and forwarded to the head unit.

In vehicles except code 810 (Sound system) and except code 853 ("Midline" sound system), the head unit outputs the audio signals according to the volume and sound settings via the speaker system of the vehicle.

In vehicles with code 810 (Sound system), the head unit transmits the audio signals and the volume and tone settings via MOST to the sound system amplifier control unit, which actuates the speaker system.

In vehicles with code 853 ("Midline" sound system), the head unit transmits the audio signals and the volume and tone settings via the MOST to the Midline sound system amplifier control unit, which actuates the speaker system.

IMPORTANT Because the head unit supports the Internet radio function, radio reception is possible via the Internet with a valid subscription.

Audio mode comprises the following subfunctions:

Volume and tone settings 

All volume and tone settings are selected using the head unit. This is performed either by the user or automatically by the head unit with the aid of the speed-dependent volume control (SDV). The sound settings are shown on the Audio/COMAND display. The sound settings can be changed individually for applications with the "Sound" menu and the system returned to the default settings via the system settings. On vehicles with code 810 (Sound system) or code 853 ("Midline" sound system), the head unit has additional sound settings.

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

Manual volume and tone settings 

Manually volume and tone settings can be selected as follows:

IMPORTANT The audio output via the speaker system is interrupted by operating the mute function button (S163/1s9) in the instrument cluster multifunction steering wheel button group (S163/1) or by pressing the volume control button.

SDV 

The volume is adapted to the noise situation in the vehicle interior with the help of the speed-dependent volume control. The noise level in the vehicle interior is determined via the vehicle speed, whereby the assignment depends on the respective body variant. The instrument cluster transmits the vehicle speed data to the head unit via the user interface CAN. Corresponding to this information, the head unit, the sound system amplifier control unit (with code 810 (Sound system)) or the "Midline" sound system amplifier control unit (with code 853 ("Midline" sound system)) increases or lowers the output level. In vehicles with code 810 (Sound system) or with code 853 ("Midline" sound system), the SDV is additionally optimized by interference detection with the driver hands-free system microphone and the front passenger hands-free system microphone. The sound system amplifier control unit (with code 810 (Sound system)) or the "Midline" sound system amplifier control unit (with code 853 ("Midline" sound system)) receives the signals of the driver hands-free system microphone or of the front passenger hands-free system microphone via MOST from the head unit, evaluates the signals and adapts the volume of the audio signals to the interior or driving noises.

Radio mode (FM, AM, HD radio) 

The antennas receive signals for the frequency bands FM (ultra-short wave) and AM (medium wave, not available in all national versions). The following useful signals relevant for the radio reception are modulated onto these signals:

Vehicles with code 494 (USA version) or code 460 (Canada version) are equipped for reception of HD radio. In HD radio, digital signals are sent over the radio frequencies along with the analog signals. This makes audio signals available in better reception quality, and additional information and services can also be received and used. These signals are processed by the audio tuner integrated in the head unit.

In model 205.0/1/3, the head unit receives the FM 1 and FM 2 signals or the HD radio signals via the rear window antenna and the FM 1, AM, CL and KEYLESS-GO antenna amplifier and the FM 2 and DAB band III antenna amplifier.

In model 205.2, 253.99, the head unit receives the FM 1 and FM 2 signals or the HD radio signals via the rear spoiler antenna and the FM 1, AM, CL and KEYLESS-GO antenna amplifier.

In model 205.4, the head unit receives the FM 1 and FM 2 signals or the HD radio signals via the windshield antenna and the FM 1, AM, CL and KEYLESS-GO antenna amplifier or the FM 2, DAB and TV 1 antenna amplifier.

In model 205.0/1/3, the head unit receives the AM signals via the rear window antenna and the FM 1, AM, CL and KEYLESS-GO antenna amplifier.

In model 205.2, 253.99, the head unit receives the AM signals via the rear spoiler antenna and the FM 1, AM, CL and KEYLESS-GO antenna amplifier.

In model 205.4 with closed soft top, the head unit receives the AM signals via the soft top AM antenna, the AM amplifier, the AM amplifier with selection switch and the FM 1, AM, CL and KEYLESS-GO antenna amplifier.

In model 205.4 with open soft top, the head unit receives the AM signals via the left rear side wall trim antenna, the AM amplifier with selection switch and the FM 1, AM, CL and KEYLESS-GO antenna amplifier.

IMPORTANT Operating electrical or electronic devices (e.g. USB chargers) inside the vehicle can significantly impair the reception quality.

Radio mode involves the following components:

AM tuner 

For the MW, LW and SW radio frequency bands, the useful signals are broadcast using amplitude modulation (AM). The AM tuner integrated into the head unit 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.

Dual FM tuner with multipath reception (FM) 

For the FM radio frequency band, the useful signals are broadcast using frequency modulation (FM). The FM twin tuner integrated into the head unit demodulates these signals. In other words, it separates the useful signals (audible frequencies) from the carrier signal (inaudible). The head unit integrates the useful signals from the FM 1, AM, CL and KEYLESS-GO antenna amplifier and from the FM 2 and DAB band III antenna amplifier (model 205.0/1/3) or the FM 2, DAB and TV 1 antenna amplifier (model 205.2/4, 253.99) into an optimized signal (phase diversity).

IMPORTANT An additional tuner function for the FM multiplexer is integrated in the head unit for the Vehicle Information and Communication System (VICS) additional information.

RBDS (with code 494 (USA version) or code 460 (Canada version)) or RDS (except code 494 (USA version), except code 460 (Canada version) and except code 498 (Japan version)) 

In addition to the radio program, many radio stations (FM) also broadcast additional digital information such as station name, type of program and traffic message channel recognition. This information is evaluated by the head unit and shown on the Audio/COMAND display, if an RDS or RBDS station is tuned and the RDS or RBDS function is activated.

HD radio (with code 494 (USA version) or code 460 (Canada version)) 

The audio tuner integrated in the head unit decodes the digital signals. Additional information and services are shown on the Audio/COMAND display, e.g. program service data, artist experience, traffic information.

Additional function requirement for SD card (with code 355 (Pre-installation for navigation retrofit), with code 357 (Card navigation) or code 531 (COMAND APS)) 

SD card (with code 355 (Pre-installation for navigation retrofit), with code 357 (Card navigation) or code 531 (COMAND APS)) 

The SD card slot is integrated in the multimedia connection unit. The head unit reads in the signals of the multimedia connection unit. Audio files stored on an SD card can be shown on the Audio/COMAND display by activating the "Memory Card" media source and played back by the head unit.

Additional function requirements for multimedia connection unit 

Multimedia connection unit 

USB port 1 and USB port 2 of the multimedia connection unit, the front center console USB port (with code 896 (Vehicle access and drive authorization via mobile phone), code 897 (Wireless mobile phone charging) or code 899 (Multifunction telephony)) can be used to connect external devices (e.g. audio player, USB (Universal Serial Bus) memory stick, iPods, MTP devices). The multimedia connection unit and the front center console USB port are connected to the head unit through direct lines.

IMPORTANT Three adapter cables are enclosed for connecting the external devices.

When playing pieces of music, the corresponding cover art is shown on the Audio/COMAND display if the cover art in question is stored in the portable terminal (e.g. iPod and USB). The head unit adapts the resolution and converts the file into JPG format. When searching for albums or pieces of music on the connected device, the corresponding cover art is also shown on the Audio/COMAND display.

IMPORTANT The cover art is additionally displayed in the instrument cluster.

DAB (with code 537 (Digital radio (DAB))) 

The tuner unit integrated in the head unit enables the reception of digital radio in DAB format. With DAB, the stations are categorized into groups known as "Ensembles". The signals are transmitted as DAB band III signals. Control of the DAB functions is accomplished via the head unit. The information or displays required for control are shown on the Audio/COMAND display.

To ensure reception diversity (selection of the best signal), the head unit receives two DAB band III signals.

In model 205.0/1/3, the head unit receives the DAB band III signals via the FM 2 and DAB band III (DAB II) antenna amplifier and the FM 1, AM, CL and KEYLESS-GO (DAB I) antenna amplifier from the rear window antenna.

In model 205.2, 253.99, the head unit receives the DAB band III signals via the FM 2, DAB and TV 1 (DAB II) antenna amplifier and the FM 1, AM, CL and KEYLESS-GO (DAB I) antenna amplifier from the rear window antenna.

In model 205.4, the head unit receives the DAB band III signals via the FM 2, DAB and TV 1 (DAB II) antenna amplifier and the FM 1, AM, CL and KEYLESS-GO (DAB I) antenna amplifier from the windshield antenna.

The FM double tuner provides the FM audio signals when the DAB mode is active. If the DAB reception starts to deteriorate, reception switches over to the FM station, but only after checking and ensuring a better signal reception. In this case, the head unit compensates the time lag between the digital and the analog signal. This makes the switchover almost inaudible ("seamless linking").

The DAB tuner unit is designed as a diversity tuner and provides the following advantages:

IMPORTANT Operating electrical or electronic devices (e.g. USB chargers) inside the vehicle can significantly impair the reception quality.

SDARS (with code 536 (SIRIUS satellite radio)) 

The head unit receives the "Sirius satellite radio" over the provider's transmitter SDARS antenna. The SDARS system is controlled by the head unit. The information or displays required for control are shown on the Audio/COMAND display.

To achieve a diversity of channels, the Sirius satellite radio signal is broadcast 3 times (using two satellites and one terrestrial transmitter). All three channels of the SIRIUS satellite radio (Sat 1, Sat 2, terrestrial station) are received by the SDARS antenna.

Additional function requirements for Bluetooth® Audio 

Bluetooth® Audio 

The Bluetooth® antenna allows the head unit to receive Bluetooth® audio signals from external devices. Bluetooth® audio is divided into the following additional information:

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 Profile (AVRCP) and Advanced Audio Distribution Profile (A2DP), and for telephony it is the hands-free profile (HFP). If a device supports both functions, it appears in both lists after 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 device so that it can then be controlled via the head unit.

When starting, the head unit proceeds with the following strategy: On vehicles with code 899 (Multifunction telephony) or code 897 (Wireless mobile phone charging), the head unit searches for both mobile phones that were last signed on, first via the Near Field Communication and then via Bluetooth®. The first mobile phone to respond to the request is connected.

If no mobile phones are found via near-field communication, the head unit searches for the last two mobile phones used in the vehicle. If one of these devices is found, the head unit 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 equipment connected" is shown on the head unit if the corresponding audio sources are shown in the device list. The "Connect last device" menu 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 head unit 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 head unit finger navigation pad (S163/2s10).

IMPORTANT Notes on supported devices for Bluetooth® Audio can be found under the appropriate webpage:

  Electrical function diagram for audio mode function   PE82.60-P-2058-97FBB
  Overview of system components, telematics   GF82.85-P-9999RF 
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