It is a wonderful device! I have a Kenwood Excellon PS907 CD/tuner set as my primary source and use the Empeg as the alternate source (both in the dash.) The Empeg's aux connects to a RCA to male miniplug that terminates in my center console where I can hook up a portable minidisc or even a cassette walkman. All these options are only possible because of the tiny automatic Sony switchbox.
When I slide the Empeg out, the Sony switches to the other head unit. It works on the "amp feed line" outputs. If I turn on the other head unit, the Sony will also switch to it. I turn it off to return to the Empeg.
Also, I have music even without the empeg.
Regards,
Mark
--> Get paid to surf the web! http://www.alladvantage.com/go.asp?refid=CCI498