Audio mode, function - GF82.85-P-2030CWD

MODEL 204.0 with CODE (510) Audio 20 with CD changer 

MODEL 204.2 with CODE (510) Audio 20 with CD changer 

Function requirements 

• Status "circuit 30 ON" or "circuit 15R ON"
• The radio is authorized and in perfect working order
• No fault in antenna system (radio function)
• Data CD is inserted
• A Radio Broadcast Data System (RBDS) station is set and the RBDS function active (for vehicles with code (494) USA version)
• A Radio Data System (RBDS) station is set and the RDS function active (for vehicles except code (494) USA version)
• The radio station also transmits additional digital information
• The Traffic Announcement (TA) function is set on the radio (for vehicles except code (494) USA version)

General audio mode function sequence 

The audio mode consists of the following component functions:

• Radio mode function sequence (AM/FM)
• Function sequence for audio CDs as well as MP3 (on CD)
• Function sequence for Digital Audio Broadcasting (Digital Radio) (DAB) (with code (537) Digital radio)
• Function sequence for Satellite Digital Audio Radio (satellite radio) (SDAR) (with code (536) SIRIUS satellite radio)

Operating instructions 

The audio functions can be controlled, or selected and set, using the following components:

• Left multifunction steering wheel button group (S110) or right multifunction steering wheel button group (S111)
• Audio/COMAND control panel (A40/9)
• Control buttons on the radio (A2)

Radio mode function sequence (AM/FM) 

The antennas in the rear window receive high frequency (HF) signals for the FM and AM (MW, LW) radio frequency bands. The following useful signals relevant for the radio reception are modulated onto these HF signals:

• Music signals
• Speech signals
• Data signals (e.g. weather information)

The HF-signals are sent over discrete lines to the FM, AM and central locking antenna amplifier (A2/18) (model 204.0) or rear window antenna amplifier 1 (A2/71) (model 204.2) as well as to the antenna amplifier for the rear window FM antenna (A2/19). These amplifiers filter the frequencies of the radio frequency bands out of the received HF signals and amplify them. The amplified signals are then sent via coaxial cable (FM, AM) to the tuner integrated in the radio where they are demodulated. The demodulated audio signals on vehicles with code (810) Sound system are sent by the radio over the Media Oriented System Transport (MOST) to the sound system amplifier (N40/3) and finally amplified.

The audio output then takes place over discrete lines by the following speakers:

• Left front door speaker (H4/1)
• Right front door speaker (H4/2)
• Left rear door speaker (H4/3)
• Right rear door speaker (H4/4)
• Center instrument panel speaker (H4/27)
• Bass speaker (H4/29)
• Left rear surround speaker (H4/54)
• Right rear surround speaker (H4/57)

On vehicles except code (810) Sound system, the audio output takes place over discrete lines via the radio through the following speakers:

• Left front door speaker
• Right front door speaker
• Left rear door speaker
• Right rear door speaker
• Center instrument panel speaker

The radio mode function sequence consists of the following component functions:

• AM tuner (MW, LW, SW) function
• FM dual tuner with phase diversity (FM)
• Radio Broadcast Data System (RBDS)
• Radio Data System (RDS), function

AM tuner (MW, LW) function 

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).

FM dual tuner with phase diversity (FM) 

For the FM radio frequency band, the useful signals are broadcast using frequency modulation (FM). The FM tuner integrated into the radio demodulates these signals. In other words, it also separates the useful signals (audible frequencies) from the carrier signal (inaudible). The radio also enables an additional reception-specific changeover between the two antenna amplifiers. This function runs automatically.

RBDS or RDS function 

Digital, inaudible information such as station names, types of program (PTY) (e.g. pop, classic) is evaluated by the radio and shown on the Audio/COMAND display (A40/8).

Function sequence for audio CDs as well as MP3 (on CD) 

A 6-disk CD changer is integrated into the radio. The CD changer is used to read in the audio CDs (including in MP3 format) and they are internally processed by the radio. The user interface for controlling the CD functionality (e.g. track selection) and for displaying supplemental information (e.g. title) is on the Audio/COMAND display.

The CD menu and the Title menu, which are stored on the inserted CD, and the CD slots that are occupied, are shown on the Audio/COMAND display. Slots "1" to "6" are numbered consecutively. This is why the functional scope and menu display are dependent on the actual CD inserted.

For vehicles with code (810) Sound system, data exchange takes place between the radio and the sound system amplifier control unit (N40/3) over MOST. The audio signal output then takes place over discrete lines at the following speakers:

• Left front door speaker
• Right front door speaker
• Left rear door speaker
• Right rear door speaker
• Center instrument panel speaker
• Bass speaker
• Left rear surround speaker
• Right rear surround speaker

On vehicles except code (810) Sound system, the audio output takes place over discrete lines via the radio through the following speakers:

• Left front door speaker
• Right front door speaker
• Left rear door speaker
• Right rear door speaker
• Center instrument panel speaker

	Digital Audio Broadcasting (DAB), function	With code (537) Digital radio	GF82.60-P-3020CWA
	Satellite digital audio radio (satellite radio) (SDAR) function	Model 204.0 With code (536) SIRIUS satellite radio	GF82.60-P-3021CWA