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

MODEL 453.0/3/4 

with CODE 535 (smart Media system) 

except CODE 537 (smart Audio system) 

G12096482Courtesy of MERCEDES-BENZ USA

Shown with code K36 (instrument cluster with 8.9-cm (3.5") color display) 

Function requirements, audio mode, general 

General information on the audio mode 

The audio mode consists of the following component functions:

Audio mode functions are selected using the following controls:

In vehicles except code 810 (Sound system), the smart radio multimedia navigator outputs the audio signals over the vehicle's speaker system. In vehicles with code 810 (Sound system), the smart radio multimedia navigator forwards the audio signals 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. The Smart Media System has diagnosis capability, and the fault memory can be interrogated via the diagnostic connector using XENTRY Diagnostics.

Function sequence for volume and sound settings 

All volume and tone settings are made via the Smart Radio Multimedia Navigator. This is performed either by the user or automatically by the Smart Radio Multimedia Navigator. The volume and tone settings are shown on the Smart Radio Multimedia Navigator display. The audio settings can be changed using "Multimedia" "Settings" "Sound" and the manufacturer default settings can be restored through System settings. In vehicles without code 810 (Sound system), as well as the general sound settings (balance, bass/treble) the smart radio multimedia navigator is also equipped with the "Arkamys" bass boost effect sound setting.

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

Function sequence for manual volume and sound settings 

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

IMPORTANT In vehicles with code 810 (Sound system), the desired settings are forwarded over the telematics CAN, radio to the sound system amplifier control unit, where they are processed. In vehicles without code 810 (Sound system), the selected settings are forwarded via the telematics CAN to the radio, where they are processed. Audio output via the speaker system is interrupted by pressing the mute function button or using the corresponding button on the Smart Radio Multimedia Navigator.

Function sequence for speaker settings using the right multifunction steering wheel button group (only vehicles with code K36 (Instrument cluster with 8.9 cm (3, 5") color display)) 

Specific functions and the volume adjustment are set by pressing the volume (+) button and volume (-) button, which increases or decreases the volume for the audio sources.

The control signals are forwarded to the radio via the following route:

Function sequence for volume and tone settings via Smart Radio Multimedia Navigator 

Operating the control on the Smart Radio Multimedia Navigator increases or reduces the volume.

Function sequence for speed-dependent volume adjustment 

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 audio gateway control unit transmits vehicle speed information to the radio via telematics CAN. The audio gateway control unit receives this information about the vehicle speed from the Electronic Stability Program control unit, which reads in the signals of the rear axle rpm sensors to calculate the vehicle speed and transmits it to the instrument cluster and the audio gateway control unit via the interior CAN. The Smart Radio Multimedia Navigator receives the vehicle speed signal via the telematics CAN and adapts the volume to the speed displayed in the instrument cluster.

In vehicles with code 810 (Sound system), the audio gateway control unit forwards vehicle speed information to the sound system amplifier control unit via the telematics CAN.

The radio increases or decreases the output level depending on this information.

Function sequence for radio mode function (FM/AM) 

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

The radio receives the FM-1, FM-2 and AM signals through direct lines from the FM, AM and DAB antenna. The frequency bands can be switched over using the frequency selection button on the top left in the touchscreen, e.g. from "FM 1" to "FM 2" or "AM".

Radio operation is activated via the menu items "Main menu/Multimedia/RADIO" on the Smart Radio Multimedia Navigator touchscreen. 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 radio demodulates these signals. In other words, it separates the useful signals (audible frequencies) from the carrier signal (inaudible).

Dual FM 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 in the radio demodulates these signals. In other words, it separates the useful signals (audible frequencies) from the carrier signal (inaudible).

Function sequence for radio data system (RDS) 

As well as the radio program, many radio stations on FM also broadcast additional digital information such as the station name and traffic message channel recognition. This additional information is evaluated and displayed on the touchscreen of the Smart Radio Multimedia Navigator, provided that the following requirements are met:

Function sequence for digital radio (DAB) (with code C04 (Digital radio (DAB))) 

The tuner unit integrated into the radio permits the reception of digital radio in DAB format. It is possible to switch over to DAB reception using the frequency selection button on the top left in the touchscreen, e.g. from "FM 1" to "DR 1" or "DR 2". With DAB, the stations are categorized into groups, so-called "Ensembles". The DAB functions are controlled via the Smart Radio Multimedia Navigator. The information and displays that are required for operation are output via the touchscreen of the Smart Radio Multimedia Navigator. The tuner unit in the radio receives the DAB signals as DAB band III signals.

The tuner unit receives the DAB signals via the FM, AM and DAB antenna

Reception-specific switchover from DAB to FM 

The radio transmits the FM station lists to the tuner unit. If a comparable FM station is found, it is requested by the tuner unit. If the DAB reception starts to deteriorate, the radio switches to the FM station.

Function sequence, multimedia connection unit 

The Universal Serial Bus (USB), Secure Digital (SD), auxiliary (AUX) and Bluetooth® audio sources can be called up through the "Main menu/Multimedia/Media/Media selection" menu items on the smart radio multimedia navigator touchscreen. An appropriate distinction must therefore be made between the following function sequences during media operation:

The multimedia connection unit can be used to connect external devices (e.g. USB stick) via USB, SD and AUX and they can be read in (e.g. SD card) or connected through Bluetooth®. The multimedia connection unit is connected to the radio via the Smart Radio Multimedia Navigator. When the media source is activated, the radio outputs the audio data from the connected devices over the speaker system or forwards it directly to the sound system amplifier control unit (with code 810 (Sound system)).

Function sequence for Bluetooth® audio 

The radio can receive Bluetooth® audio signals from external devices via the Bluetooth® antenna. 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 Audio/Video Remote Control Profile (AVRCP) and Advanced Audio Distribution Profile (A2DP) Bluetooth® profiles are needed for Bluetooth® audio and the Hands-Free Profile (HFP) is needed for telephony. 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 HFP, AVRCP and A2DP, all profiles are connected. In this case the device is a telephone and the source of Bluetooth® audio at the same time.

With the majority of devices, the player must be started on the telephone so that it can then be controlled via the Smart Radio Multimedia Navigator.

The radio uses the following strategy when starting: First it is checked whether an authorized telephone has been placed in the mobile phone cradle. If this is the case, the radio connects to the telephone and is in comfort telephony status. If no mobile phone cradle is present or no telephone has been inserted, the radio searches for the last two telephones.

If one of the last two telephones is found, the radio connects itself to this device. If this device also supports AVRCP or A2DP, these profiles are also connected.

If a device is connected that only supports HFP and the system is switched to the Bluetooth® audio application, "No Bluetooth® audio device connected" appears on the touchscreen of the Smart Radio Multimedia Navigator, provided that appropriate 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 or A2DP and the system is switched to the telephone application, the connection to the device is disconnected and the radio starts to 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, then only "Audio streaming" is shown on the radio display.

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 support to rental car head office (vehicles with code P02 (car2go) or code 54P (Line package rental Model)) 

IMPORTANT Depending on the car2go system variant involved, the GSM/UMTS antenna is either integrated into the windshield reader system control unit or in the telematics services communications module (N112/2) or an additional, external GSM/UMTS antenna was installed in the vehicle.

The customer can communicate with rental car head office audio support via the hands-free system of the smart media system. The smart radio multimedia navigator forwards the hands-free system microphone signals via the audio wiring to the windshield reader system control unit and receives the signals from the rental car head office via the audio line for voice output via the smart media system speakers. The windshield reader system control unit establishes the telephone connection via the GSM/UMTS antenna. Data exchange, e.g. for operating requirements, between the smart radio multimedia navigator and the windshield reader system control unit takes place via a USB connection. The card data of the customer is read in by the card reader and transmitted via the car2go LIN to the windshield reader system control unit.

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