PAC's OS-1 interface lets you replace any General Motors radio (without RDS) while maintaining operation of the OnStar® system. The OS-1 has on-board switching and built-in amplification that allows audio from the OnStar® system to play through the two front factory speakers when OnStar® is active, while muting the replacement radio.
The OS-1 can also send OnStar® audio to an external set of speakers if desired. There are separate right and left gain controls for OnStar® audio, and an LED indicator that turns on when the OS-1 receives an "On" command from the OnStar® system. Dimensions: 4-13/16"W x 1-1/16"H x 2"D. 1-year warranty.
Note: The OS-1 will interface with all GM radios that do NOT have the "RDS" option — it works with Bose and standard GM radios. If there is an "RDS" logo on the radio face, the OS-1 will not work.