Remote Start & Security Interfaces Reference Guide http://www.xpresskit.com/index.aspx

The DEI 1701G interfaces with specific GM vehicles. It converts the signals from the keyless entry, alarm, or remote starter into signals that can be understood by the vehicles factory data bus system. This allows for interfacing with various factory options such as factory remote start, alarm and keyless entry. This unit can be used to interface an aftermarket keyless entry, alarm or remote starter to the new vehicle.

Directed Electronics 1701G GM Door Lock And Remote Start Databus Interface Module