GF82.60-P-2000TXU Audio Functions

GF82.60-P-2000TXU Audio Functions
- with CODE (494) USA version
- Radio mode and CD mode

Component Identification:

Radio mode, function
After activation of the "Radio mode" function in the "Audio" menu by pressing the "FM/AM" button on the COMAND operating, display and control unit, the antennas in the rear window receive high frequency signals for ultra-short wave (FM), medium wave (MW) and the weather band (weather information channel). Modulated onto these high frequency signals are the music, language and data signals. The left antenna amplifier module filters the frequencies of the radio frequency bands out of the high-frequency signals received and amplifies them. The amplified signals are then sent over a coaxial cable to the radio tuner, which is integrated in the audio gateway control unit. The radio tuner separates the useful information (audible frequencies) from the carrier signal (inaudible).

The demodulated audio signals are amplified and converted to sound signals by the vehicle speakers.

Antenna diversity, function
In the case of the "antenna diversity" function, reception-specific switching over is carried out between the rear window FM antennas. The function runs automatically and is carried out by the left antenna amplifier module. The radio tuner in the audio gateway control unit merely generates the intermediate frequency (IF) signal, which in turn serves as a reference for changing the FM antenna.

2-receiver technology function
A 2nd (integrated) radio receiver in the audio gateway control unit automatically generates a list of received FM stations once the COMAND operating, display and control unit has been switched on, which is constantly updated during operation. This list appears, sorted alphabetically, when the "FM station list" menu is called up. The stations which are displayed can be activated by selecting and confirming.

The list of stations is only available when the "Radio Broadcast Data System (RBDS)" function has been activated. If reception faults occur while driving, the COMAND operating, display and control unit attempts to receive the selected station on an alternative frequency with the aid of the 2nd radio receiver and to switch over accordingly if reception improves.

RBDS function
In addition to the radio program, many radio stations (FM) also transmit additional inaudible digital information. This includes, for example station names or alternative frequencies, on which the same program can be heard along with traffic program identification. This information is evaluated by the COMAND operating, display and control unit and shown on the display if:
^ An RBDS station has been tuned to
^ The "RBDS" function has been activated

The radio components in the audio gateway control unit also offers:
^ a station list of the currently most powerful FM stations in RBDS mode
^ an automatic memory for the strongest AM stations
^ a selection of program type (e.g. pop, culture, etc.) for FM stations in RBDS mode

Station selection options are:
^ automatic station search with scan function (the stations of one waveband are played for 8 s)
^ station search at the multifunction steering wheel (MFL)
^ Manual station search
^ Station selection with station list
^ Station selection with number buttons
^ Station selection by entering the frequency (e.g. 92.2 MHz)
^ station selection from the memory (10 stations per waveband)

CD mode function
The COMAND operating, display and control unit also comes with an integrated CD disk drive, which is used to play back audio CDs.

CD changer mode (with code (819) 6-disk CD changer)
The CD changer is controlled by the COMAND operating, display and control unit.

The control signals and audio data on the CD changer are transmitted by the Media Oriented System Transport (MOST). In doing so, the control signals are forwarded to the other system components, but the audio data to the audio gateway control unit only.

Only audio CDs can be used as media in the CD changer and they must have the appropriate file format.

The COMAND operating, display and control unit in combination with the CD changer provides the following functions:

^ "Scan" function
Either the tracks of a CD are played or the 1st track of the CDs of the entire magazine is played for 8 seconds. After this has been run through completely, the scan function is automatically terminated.
^ Fast forward and rewind (music search)
Music played is audible during fast forward and rewind. Certain parts of a title can therefore be specifically played or skipped.
^ "Random" function
All the titles on a CD or the entire CD magazine are played in accordance with the random principle.
^ "Repeat" function
Alternatively a title, a CD or the entire CD magazine is repeated.

CD title allocation, function
Each CD contains a permanently stored table of contents (TOC entry). As a result, the operating module clearly recognizes the particular CD, and is able to automatically name it after the onetime user allocation of the title (even if the CD is inserted in another CD magazine).

The table of contents (TOC record) also contains information on the number of tracks on a CD and the total playing time of the CD.

In vehicles as from 1.6.05, the CD disk drive integrated into the COMAND operating, display and control unit and the CD changer can also play audio CDs in MP3 format.