Voice control code to enable voice on car that already has bluetooth?
I'm looking at ways of getting my car voice control-enabled. I've done a bit of research, and found that you can get the voice control feature by simply replacing my car's existing bluetooth-but-no-voice module for one that does have voice. Having said that, as far as I can make out (and having read up on modules with voice), it seems to me as though the modules (voice, or no voice) are actually the same, and the only difference is that the ones with voice have been 'coded' to allow the voice section to function.
1. Can anyone tell me if that's true, and...
2. Can anyone offer advice on how I go about coding my existing unit, rather than having to buy another (identical, by the sounds of it) one?