Using an after market radio unit
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The accessory electronic module (AEM) (4/78) makes it possible to automatically control the telemute function, display lighting and speed-adapted volume control when using an aftermarket radio unit. This is on the condition that the aftermarket radio unit supports these functions. The accessory electronic module (AEM) receives a speed signal (volume adaptation) via the CAN-net and brightness of the display lighting via rheostat from the central electronic module (CEM) (4/56).
The accessory electronic module (AEM) also receives a mute signal from the reverse warning system and external hands-free unit and transmits it on to the radio unit.