I'm working on this myself; unfortunately, it seems that the only way to get it to talk to the standard head unit is to hook up a CD changer to the head unit, and then usurp the audio connections (that is, until I reverse-engineer the head unit <-> CD changer communication protocol and program the empeg's serial port to fool the head unit into thinking it's a CD changer :)... My install ought to be done by the end of this week (just got some needed parts from VW today)...

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Daniel M. Zimmerman
Caltech Computer Science
[email protected]