HMMM...I need to test this with my Scion xB. I have noticed that when I have the iPhone hooked up with the special Scion cable and while listening to music, when I receive a call the ringer rings through my car speakers. I have always unplugged the phone when answering the call so I would like to see if I can hear the caller through my speakers.
The mic, of course, would be on the phone, and I don't know if the cable allows two-way transmission.
If yours is like mine in which I am running directly into my Volvo C70, I have to unplug the phone. The ringer comes through the speakers but the actual call will not. A real PITA, I wish I could just leave it plugged in. Any developers out there want to do something about this?