2000 GMC Envoy Owner's Manual - Page 154

Rear Seat Audio (RSA) headphones while the driver listens to the radio through the front speakers. The rear seat passengers have control of the volume for each set of headphones. Be aware that the front seat audio controls always have priority over the RSA controls. Note that if the front seat passengers switch the source for the main radio to a remote source, the RSA will play the same remote source. The rear speakers will be muted when the RSA power is turned on. You may operate the RSA functions even when the main radio is off. Note that this feature is intended for rear seat passengers. The following function is controlled by the knob on the main radio: PWR-VOL: Push this knob twice to turn RSA off. The following functions are controlled by the RSA system buttons: This feature allows rear seat passengers to listen to and control any of the music sources, including AM-FM, cassette tapes and CDs, through the Rear Seat Audio (RSA) controller. However, the rear seat passengers can only control the music sources that the front seat passengers are not listening to. For example, rear seat passengers may listen to a cassette tape through PWR: Press this button to turn RSA on or off. VOL: Press this knob lightly so it extends. Turn the knob clockwise to increase volume and counterclockwise to decrease volume. Push the knob back into its stored position when you're not using it. The left VOL knob controls the left headphone and the right VOL knob controls the right headphone. 3-17