Has anyone tried to get the track info from the serial port and convert it to ntsc/rgb for this use?
Yes,
right here.
Also, has anyone hacked the volume to fix it @ a certain level (ie 0db gain) and not make the volume control available on the Empeg unit?
Yes, that is a kernel hack. I'm sure I read somebody doing it once, but I have been unable to locate that thread in a search.
However, you might not need it. The Empeg remembers its volume setting for the car separately from the volume setting for the house. So if you just set it at 0db and leave it, it will stay there.
If you're complaining that the empeg is responding to commands from an IR remote for your head unit, there are also kernel hacks available that will make it ignore certain IR inputs. Again, I don't have the link to that but I'm pretty sure it exists.
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Tony Fabris