Audio Module (AUM) (2001-2007): Function
The audio module (AUM) functions as a sound unit in the car and is also connected to other control modules on the Controller area network (CAN). The audio module (AUM) receives the vehicle speed signal via the Control area network (CAN). Volume increases with speed (if the function is selected; the function can be switched off).
If a factory-installed carphone (option) is installed, the audio module (AUM) is muted during telephone calls.
If an accessory electronic module (AEM) is installed, the audio module (AUM) is muted if either a handsfree telephone is used (accessory) or back-up gear is selected if the car has a back-up warning system (accessory).
If the car has the Road Traffic Information system (RTI) (option), voice information is played back through the existing loudspeaker.
The keypad for remote operation (option) on the steering wheel is directly connected to the steering wheel module (SWM) via serial communication. The remote control keypad is on the right-hand side of the steering wheel. It is possible to control the volume (increase-decrease) and change the preprogrammed radio stations via remote operation. The buttons are used to select a track when playing a CD, cassette or Mini-Disk.
The steering wheel module (SWM) communicates with the audio module (AUM) via the Controller area network (CAN).