Main unit: General

The main unit for the telephone system is the audio system main unit. It is connected to the wiring harness and the bus via a 26-pin connector.

The main unit performs the following tasks:

• Disconnects the normal sound from the selected source during a telephone call. This is achieved by sending a mute signal to the main unit, which then disconnects the normal sound to the speakers and the signal to the external amplifier where relevant.
• Receives the audio signal (line input) from the telephone (incoming sound) via the telephone contact and reproduces it via the audio system speakers.

See TEST READINGS, CONTROL MODULE CONNECTIONS .