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Home >> Cadillac >> 2007 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 1232 (Cellular System, Entertainment System, And Navigation System) >> Diagnostic Information and Procedures >> Unable to Contact OnStar Call Center >> Circuit/System Description
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Circuit/System Description

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The communication interface module (CIM) is a cellular device that allows the user to communicate data and voice signals over the national cellular network. When an OnStar keypress is made, the CIM activates and connects the system to the cellular carriers communication system by interacting with the national cellular infrastructure. The module sends and receives all cellular communications over the cellular antenna and cellular antenna coax.