saknife:
Yeah, I was looking into the onstar hack, although I have only found hacks for the 2 piece system. This is a one piece onstar unit, from 2003. If you could help me with finding the sites, that would be great. Also It would have to be USB since I would be using a mac, and well the days of RS232 are long gone for them. Any idea?
Hm… Haven’t seen anything about one piece units, but that doesn’t mean the info isn’t out there. I did come across this thread (http://www.mp3car.com/vbulletin/showthread.php?t=75346) about using the antenna with another GPS Receiver.
I don’t know much about Macs, but my guess is an off-the-shelf RS232 → USB converter would work well if you’re interfacing with an off-the-shelf device. If you’re interfacing with a GPS module that has TTL-level outputs, you’d end up using something like the FT232RL sold here (or the USB eval boards which have that chip built in).