The CD changer (CD Changer CDC / Multimedia Changer MMC) is a separate control module in the MOST framework. The requests for the particular functions can be issued by various control modules.
The Audio CD changer serves to automatically play individual CDs or several CDs in succession from a magazine. The order in which the CDs or the tracks on the CDs are to be played can be freely selected.
The Control Display (CD) and Central Information Display (CID) are separate components. The Control Display (CD) with the Central Information Display (CID) and the Controller (CON) contains the operation and display elements for the vehicle electronics, with the exception of the ADP functions.
The Control Display (CD) co-ordinates the function requests from the system and assigns them to the individual functions. For the Control Display (CD), the following is displayed on the tester:
The Central Information Display (CID) is the display unit. For the Central Information Display (CID), the following is displayed on the tester:
All the functions of the video module 5 Drive can be displayed on the Central Information Display (CID) via RGB signals (red-green-blue signals).
The Controller (CON) is the control element for the Control Display (CD) with the display unit Central Information Display (CID). To run operating functions, the front Controller (CON) is folded out of the center armrest.
The Audio Display Panel (ADP) is the operation and display unit for the audio, video and TV functions. The Audio Display Panel (ADP) incorporates an LC display, control elements and a CD player. Some control elements are firmly wired to the Audio System Controller (ASK). The remaining control elements and the LC display are connected by data bus to the Control Display (CD).
The audio system controller (ASK) is a control module in the MOST network. The ASK is the system master. The audio system controller (ASK) is responsible for management of all audio signals.
The MOST (Media Oriented Systems Transport) bus links the audio, video and navigation systems. Information relating to function requests is transmitted to the relevant control modules by means of MOST bus messages.
To achieve good sound reproduction quality, the CD changer's playback mechanism is spring-mounted. During normal driving, shocks are adequately damped in order to balance out road-surface irregularities. For the improvement of reproduction quality, the CD changer is also fitted with an electronic correction device.
Note: In the case of extremely hard suspensions or at high speeds, vibrations can occur which will cause the playback mechanism to come into contact with the housing. The electronic correction device cannot compensate for such flaws. In such cases, there will be a resulting reduction in reproduction quality.
When a CD is played, the digital information is read by a laser beam in the CD changer. The optical signals are converted into audio signals and forwarded to the audio system controller (ASK).
The CD changer's drive only contains the CD which is actually being played at that moment. Further CDs are stored in a magazine outside the CD changer.
In the CD changing operation, the CD to be played next is removed from the magazine by two rubber rollers and placed in the playback position.
The ”mute” function mutes playback by the CD changer or reduces the audio volume. It may also stop the CD player. The ”mute” function is activated by the audio system controller (ASK) on the basis of the following prioritization:
Some customer complaints cannot be put down to CD changers that are not working properly. Such complaints may be caused by poor-quality CDs or external effects on CDs.
Due to the particular conditions under which a CD changer operates in mobile applications, CDs which are outside or right at the limit of the manufacturing tolerance can give rise to problems when they are played. Causes may be:
In the case of single CDs (8 cm) with single adapter, malfunctions can occur because the CD is too thick (due to protective film, protective varnish, stabilization rings).
Note: To prevent malfunctions, only use original CDs!
In the event of a faulty Eject function, the magazine and/or the inserted CD cannot be ejected from the unit.