Schematic of a GM ALDL -> PC converter

[Markus Strobl]

Does anyone have a schematic of a GM late model ALDL to 
PC converter? By late model I mean the late 80s/90s
8192 baud ALDL. I know the Diacom package has such a 
converter and someone said it was very simple, but
I have not been able to find one. I'm planning to 
write a win95 scantool, but need to be able to 
talk to the PCM. The diacom uses one pin on the
parallell port to interface instead of the RS232 and
that would be fine. 

Markus