GM10 Trunk Connector to PC?

I'm wondering how to find specs on the control protocall the changer uses to
perhaps interface a carputer to the stock radio. I know its possible to get
RCA inputs through this connector but the device (GM10-AUX) seems a bit
overdone.

 

I'm using a PIE GM10-KNW - best "expensive thingy" ever.
Maybe I'm too critical, but FM modulation JUST DOESNT CUT IT!
I did run into a couple of problems like discovering I had to buy an
extra "wiring Harness" for the CD player from the Saturn dealership.

There are some that say MP3 doesnt sound very good. But, having
gone from an MP3 fm modulator to Direct CD connected Kenwood
player/changer - the Saturn OEM unit could never have sounded better!
Yeah - I burned audio CDs from mp3 files and they sound great.

I would think/hope that the IPOD interface should sound every bit as
good with 160k to 255k b/sec encoded MP3/s.

I have seen the wiring diagram/pinout posted, but without actually
"talking" to the controller unit in the dash, I'm not sure how you
could trick it into thinking it was hooked up to a CD unit.