Posted by mikemav at another forum:
Acura MP3 player witht he Navigation system/stereo. I do not know what protocol it uses (not familiar with CAN) but it DOES control the MP3 player with the radio controls and steering wheel controls. If you look at the Acura MP3, it does not have ANY controls on it at all except an eject button. To select it, you keep hitting the audio button on the steering wheel (it toggles from FM-1, FM-2, AM, CD, and CD-P, which is what it calls the MP3 player. You can also hit the CD/AUX button on the radio to get to that input. Once playing the Acura MP3 source, the track up/down controls work and the Navi screen shows CD-P, the track number, and the elapsed time along with random and sound buttons across the bottom.