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

GF82.85-P-2030CAD Audio Mode, Function
MODEL 207.3 /4
- with CODE (511) Audio 50 APS with DVD changer
- with CODE (525) MB Audio 50 APS radio

Function requirements, general
^ Circuit 30g ON

General information on the audio mode
The audio mode function consists of the following component functions:
^ Function sequence for radio mode (AM/FM)
^ Function sequence for audio DVD/CD as well as MP3 (on DVD/CD)
The following components are available for control of the audio system:
- Control buttons on radio with Auto-Pilot-System (A2/56)
- Audio/COMAND control panel (A40/9)
- Left multifunction steering wheel button group (S110) or right multifunction steering wheel button group (S111)
- Handsfree system microphone (A67b1) (with code (511) Audio 50 APS incl. DVD changer)
For "Circuit 15R OFF", switching on the radio with auto pilot system activates the Media Oriented System Transport (MOST) subscribers.
The audio output in vehicles without code (810) Sound system, takes place via the following speakers:
- Left door tweeter (H4/1h1)
- Left door bass speaker (H4/1h2)
- Right door tweeter (H4/2h1)
- Right door bass speaker (H4/2h2)
- Left rear tweeter (H4/3h1)
- Left rear bass speaker (H4/3h2)
- Right rear tweeter (H4/4h1)
- Right rear bass speaker (H4/4h2)
On vehicles with code (810) Sound system, the radio with auto pilot system sends the audio signals via the MOST to the sound system amplifier control unit (N40/3), which then amplifies them and outputs them over the following speakers:
- Door tweeter
- Door bass speaker
- Rear tweeter
- Rear bass speaker
- Center dashboard speaker (H4/27)
- Rear shelf bass speaker (H4/29)
- Left rear surround speaker (H4/54)
- Right rear surround speaker (H4/57)

Function sequence for radio mode (AM/FM)
The antennas in the rear window (model 207.3) receive audio signals for the FM and AM (MW, LW, SW) radio frequency bands).
For model 207.4 the radio frequency bands FM are received over the antenna in the front window. Reception of the AM frequency bands takes place for model 207.4 via the AM soft top antenna (A2/111) with a closed soft top and via the rear side paneling AM antenna with an open soft top.
The following useful signals, relevant for radio reception, are modulated onto these audio signals:
- Music signals
- Speech signals
- Data signals (e.g. traffic information)
Model 207.3
The FM signals are sent over direct lines to the FM, AM and CL [ZV] antenna amplifier (A2/18) and are routed to the rear window antenna FM antenna amplifier (A2/19).
Model 207.4:
The FM signals are sent over direct lines to the FM, AM and CL [ZV] antenna amplifier (A2/55) and are routed to the antenna amplifier TV 3, FM2 and DAB band III (A2/54). The AM signals are sent on via the AM amplifier with selection switch (A104/2) by means of a direct line to the FM, AM and ZV antenna amplifier
The AM signals from the AM soft top antenna are also amplified by the AM amplifier (A104/1).
The antenna amplifiers filter the frequencies of the radio frequency bands out of the received audio signals and amplify them. The amplified signals are then sent via coaxial cables to the tuner integrated in the radio with auto pilot system where they are demodulated and output over the speaker system.
The radio mode (AM/FM) function is made up of the following subfunctions:
^ Function sequence for AM reception (MW, LW, SW)
^ Function sequence for FM reception
^ Function sequence for radio data system (RDS) reception
^ Function sequence for Radio text+ (as of 1.6.2010)

Function sequence for AM reception (MW, LW, SW)
For the MW, LW and SW radio frequency bands, the useful signals are broadcast using amplitude modulation (AM).
The AM tuner integrated into the radio with auto pilot system demodulates these signals. In other words, it separates the useful signals (audible frequencies) from the carrier signal (inaudible).

Function sequence for FM reception
For the FM radio frequency band, the useful signals are broadcast using frequency modulation (FM). The FM double tuner integrated into the radio with auto pilot system demodulates these signals.
In other words, it also separates the useful signals (audible frequencies) from the carrier signal (inaudible).
The radio with auto pilot system also enables an additional reception-specific changeover between the two antenna amplifiers.

Additional function requirements for RDS reception
^ RDS function activated
^ Radio stations also transmit additional digital information

Function sequence for RDS reception
Apart from the normal radio program, many radio stations (FM) transmit additional digital information such as station names, program type (e.g. pop, culture) and traffic program identification.
This information is evaluated by the radio with auto pilot system and shown on the Audio/COMAND display (A40/8). The functionality in the radio with auto pilot system must be activated for this purpose.

Function sequence for Radio text+ (as of 1.6.2010)
During FM radio operation, additional information on the program can be shown on the Audio/COMAND display. For this, the "Info" softkey in the function bar must be pressed.

Function sequence for audio DVD/CD as well as MP3 (on DVD/ CD)
A DVD changer is integrated into the radio with auto pilot system for vehicles with code (511) Audio 50 APS incl. DVD changer.
On vehicles with code (525) MB Audio 50 APS radio a single DVD drive is integrated into the radio with auto pilot system.
This enables audio CDs and audio DVDs to be played (even MP3 format). User guidance for controlling DVD/CD functionality and displaying supplemental information is carried out via the Audio/ COMAND display.
The audio signals are output over the speaker system.