First gen, non-nav, Acura TSX.

Hey guys, I want to try to make my own AUX input adapter in order to add some more functionality to my media center. I bought an aux input adapter and want to start doing some reverse engineering. I figured I'd document my process here and hopefully get some help from anyone who has experience with in-car audio protocols.

I've started by probing the 14-pin connector coming out of the HU and found a line at 12V and the two BUS lines at 2.5V. I'm going to do some more probing with the unit plugged into the car and I intend to do some research on how a typical car audio bus works.

If anyone has suggestions with what to start looking for or any info at all it would be very helpful. I have access to bench supplies, oscilloscopes, etc.

 

Reserved for results