Main task

The unit contains a mobile phone and a GPS receiver. It is connected to the radio, microphone, control panel, GPS/mobile phone antenna and data link connector via the car's wiring harness. The unit is equipped with one 12-pin and two 16-pin connectors as well as an antenna connection.

The unit's main tasks in the system are the following:

• Voice and data communication via the mobile phone network.
• Receive data signals from GPS and calculate the car's position, which is transferred over the mobile hone network to the OnStar Call Centre via data communication.
• Send bus messages to activate the car horn and hazard warning lights.
• Receive bus messages if the airbag has been deployed in order to automatically call for assistance.
• Reproduce phone calls via the audio system speakers.
• Disconnect the sound of the audio system during a phone call. This is done by a mute signal being sent from the OnStar unit to the audio unit, which then disconnects the normal sound in the connected speakers and the signal to any external amplifier.
• Diagnostics communication.