Playing Back Sound

All functions in the audio module (AUD) (16/105) are controlled by the signals from other nodes in the MOST network.

To play back sound, a control module transmits a request to the infotainment module (ICM) (16/1). The infotainment control module (ICM) distributes the request to the audio module (AUD). The control module is then able to transmit signals via the MOST network to the audio module (AUD).

The infotainment control module (ICM) (16/1) processes changes to the sound, balance, bass, treble and equalizer settings. It transmits the changes via the MOST network to the audio module (AUD) (16/105) which then carries out the changes.

The control modules on the MOST network which use the audio module (AUD) to play back sound are:

• the antenna module (ATM) (16/110) for AM/FM radio
• the antenna module (ATM) (16/110) for digital radio, DAB
• the phone module (PHM) (16/60) for handsfree calls
• multimedia module (MMM) (16/108) for voice guiding (navigation)
• the MD module (MP1) (16/107) for minidiscs
• the CD module (MP2) (16/106) for compact discs.

The audio module (AUD) can generate simple sound signals which are used for example to warn the driver and passengers if there are problems. These signals are transmitted from the infotainment control module (ICM) to the audio module (AUD).

When the audio module (AUD) has received optical signals on the MOST network, these signals are sent onwards as analog signals to the directly connected front (16/4, 16/3) and rear (16/6, 16/5) loudspeakers. Certain versions of the control module have several directly connected components such as front treble speakers (16/55, 16/56), D-post loudspeakers (16/58, 16/57), center loudspeaker (16/26) and headset sockets (16/111, 16/112). The control module transmits analog signals to these components.

The microphone (16/77) is directly connected to the audio module (AUD). The microphone transmits analog signals to the control module.

When sound compensation is required, the infotainment control module (ICM) transmits sound compensation signals via the MOST network to the audio module (AUD).

Certain versions of the audio module (AUD) can also generate a digital subwoofer signal from the signal transmitted to the audio module (AUD). This signal is then transmitted via the MOST network to the subwoofer module (SUB) (16/79). The signal which is transmitted from the audio module (AUD) to the subwoofer module (SUB) is a summated and filtered loudspeaker signal.

The bass speaker signals are transmitted from the audio module (AUD) on a dedicated channel on the MOST network.

When the MOST network starts after the ignition is switched on, the infotainment control module (ICM) transmits data to the audio module (AUD) indicating whether or not there is a subwoofer module (SUB) available on the MOST network.