OnStar® Microphone
WARNING: This page is about a different car, the 2017 GMC Acadia Limited, 2017 Chevrolet Traverse, and 2017 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
The cellular microphone can be part of the rearview mirror assembly, or a stand-alone unit in the headliner or roof console. In either case, the telematics communication interface control module supplies approximately 10V to the microphone on the cellular microphone signal circuit. The microphone modifies the 10V depending on the volume and voice being detected. A cellular microphone low reference circuit or a drain wire provides a ground for the microphone. The microphone signal circuits pass through the telematics communication interface control module to support entertainment voice recognition.