http://wiki.phathack.com/Versions_and_Compatibility
http://www.phathack.com/pinouts.html
http://wiki.phathack.com/Cable_FAQ
http://wiki.phathack.com/Hardware_FAQ
There is some info for you to digest before posting this question.
With that out of the way, there are some headunits you have to have a more recent hardware revision in order to get a phatbox to work with. (some japaneese cars if I recall correctly but I don't remember which ones.. someone please PM me with that info and update the wiki page http://wiki.phathack.com/Versions_and_Compatibility for it if you would.. I'll update this thread.)
Generally you can take a VW phatbox and turn it into anything except for these newest supported headunit phatboxes. You can make a keg into anything a VW phatbox will hook up to as well.
You need the right cable for the head unit connection from the phatbox and you need the correct firmware loaded onto the phatbox / keg and it should work.
If you have general stereo related questions I suggest heading to a general car audio forum for that stuff.
What is up with the compatibility link?
Fixed.... damn spammers
Does that mean i can use the Audi Lead to plug into my Kenwood keg or is it more complicated than that?
If you have an Audi cable, and you load the Audi formware on your Kenwood Keg... yes.
I checked the Wiki but I still have a quick question. I understand that Nissan/Toyota have different hardware then the VW units. My question is, Is the Mazda Unit the Same as the Honda Unit (just diff firmware)? I think it may be but not sure.
it's the hardware compatibility links is down again
Looks like the link is down again :-(