To mute the audio on a KPS and KP-3 keypad, press and together. To un-mute the audio, press either the or button. From a remote control, press the MUTE button to mute and un-mute the audio. To select a source, momentarily press the source� button. The source s LED illuminates. Once the source is selected, you can cycle through the programmed short- press JR by repeatedly pressing the button. Press-and-hold the source button for about 3 seconds or until the source LED flashes on the keypad to access additional programmed IR commands for the source. STOP commands (when programmed) are automatically sent to the sources when the first Zone turns on, the last Zone turns off, and when the last Zone listening to a particular source switches to another source or turns off.