Thanks for the response mlord. Sorry I didn't make it clear. Instead of simply muting the unit I would like the unit to automatically switch to aux. mode when a signal is sent to the mute wire. Then one could send signals from onstar, cell phones etc. thru the aux. inputs. In otherwords a signal from a cell phone or onstar convertor box etc. would instead of muting the empeg would switch it to aux., allowing the phone or other device to automatically play thru the empeg-amp-speakers...