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Audio Mode, Function - GF82.85-S-2030TRA

Model 447.6/7 

Except Code XM0 (Facelift) 

G16501610Courtesy of MERCEDES-BENZ USA

Shown On Model 447.6/7 

Function requirements 

General information on the audio mode 

The radio (Audio) is switched on and off using the "ON" button and the volume is controlled with the volume control button. The main menu for radio reception or for media sources can be called up directly using the menu buttons on the left side on the radio (Audio). In the Audio main menu, it is possible to switch between the following audio sources:

The radio (Audio) outputs the audio signals corresponding to the volume and tone settings either via the front speakers only (model 447.6 with CODE EL8 (Two-way front speaker or model 447.7)) or on model 447.7 (with CODE EL9 (Front and rear two-way speakers)) also via the rear speakers.

The audio mode function consists of the following function sequences:

Function sequence for volume and sound settings 

All volume and tone settings are either selected directly via the radio (Audio) or via the right multifunction steering wheel button group of the multifunction steering wheel (with CODE CL4 (Multifunction steering wheel with trip computer)). Volume settings can also be controlled automatically by the radio (Audio), e.g. when a TA (Traffic Announcement) traffic information is received. The volume and sound settings are shown on the integrated display. The sound settings can be changed with the "Sound" menu and the system returned to the default settings via the system settings.

Radio mode (FM, AM) 

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

The FM, AM antenna amplifier receives the frequency-modulated and the amplitude-modulated signals via the FM, AM antenna in the windshield, filters the frequencies of the frequency bands of the radio (Audio) and amplifies them.

The FM 2, DAB antenna amplifier receives the frequency-modulated signals via the FM antenna in the windshield, filters the frequencies of the frequency bands of the radio (Audio) and amplifies them.

The amplified signals are then sent via a screened coaxial cable to the radio tuner to the radio tuner where they are demodulated and undergo final amplification.

The function sequence for radio mode also consists of the following partial function sequences:

Function sequence for AM tuner (MW, SW) 

For the MW and SW radio frequency bands, the useful signals are broadcast using amplitude modulation (AM). The AM tuner integrated into the radio (Audio) demodulates these signals, i.e. it separates the useful signals (audible frequencies) from the carrier signal (non-audible).

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 radio (Audio) demodulates these signals. In other words, it also separates the useful signals (audible frequencies) from the carrier signal (inaudible). The radio (Audio) integrates the useful signals from the FM, AM antenna amplifier and from the FM 2, DAB antenna amplifier to form an optimized signal (phase diversity).

Radio Data System (RDS) function sequence 

Besides the normal radio program, many radio stations transmit additional inaudible digital information such as station name, the program type (PTY) (e.g. pop, culture) and traffic radio recognition. This information is evaluated by the radio (Audio) and shown on the display, if an RDS station is set and the "RDS" function is activated.

2-receiver technology function 

After the radio (Audio) is switched on, a 2nd receiver for the radio (Audio) automatically generates a list of FM stations received. This list is constantly updated during operation and appears in alphabetical order when the "FM station list" menu is opened. The stations which are displayed can be activated by selecting and confirming.

IMPORTANT The station list is only available when the "RDS" function is activated. If problems in the reception occur while driving, the radio (Audio) unit tries to receive the selected station on an alternative frequency with the aid of the 2nd receiver and to switch over accordingly in the event of an improvement in reception.

Saving radio stations 

There are 10 radio station presets for each frequency band. It is possible to tune to the stations in the following ways:

Function sequence for Bluetooth® audio 

The integrated Bluetooth® antenna enables the radio (Audio) 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 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 device so that it can then be controlled through the radio (Audio).

After the radio (Audio) is switched on, it searches for the last two telephone devices. If one of these devices is found, the radio (Audio) connects to this device. If this telephone also supports AVRCP/A2DP, these profiles are also connected. If a device is connected that only supports HFP, and a change is made to use "Bluetooth Audio", the radio (Audio) shows "Bluetooth audio equipment not connected", insofar as corresponding audio sources are listed 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 device 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 interrupted and the radio (Audio) begins the search for the last two telephone devices.

Function sequence for Secure Digital (SD) memory card 

The memory card reader is integrated in the radio (Audio). In addition to original audio data on the SD card, it is also possible to output audio data in "MP3" format. The designation "MP3" is an abbreviation for MPEG 1 Audio Layer 3 and describes an audio compression standard that permits digital music signals to be compressed to approx. 8% of the original data quantity. This is done with almost no audible difference to the original signal (e.g. on an audio CD).

Universal Serial Bus (USB) mode 

External devices (e.g. audio player, USB memory stick, iPods (with CODE EN7 (Audio 15)) and MTP devices) can be connected at the USB connector of the USB/AUX connection. The electrical connector is connected to the radio (Audio) via a direct line. When connecting a device at the USB connection, the radio (Audio) switches to the new media source. The radio (Audio) reads in the data from the USB connector of the USB/AUX connection and sends control signals in the opposite route.

AUX mode 

External devices (e.g. audio player, iPods (with CODE EN7 (Audio 15)) and MTP devices) can be connected at the AUX connection of the USB/AUX connection. The AUX connection is connected to the radio (Audio) via a direct line. When connecting a device at the AUX connection, the radio (Audio) switches to the new media source. However, operation is only possible on the external media device. The radio (Audio) reads in the data from the AUX connector of the USB/AUX connection.

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