Diacom, OBDII interface (was Re: Engine codes for '84 T/A)

[Markus Strobl]

> > > PS a company called DIACOM makes software that can read the serial data and
> > > print the engine diagnostic information to a IBM PC/AT via RS232 for $300.00
> > > 800-888-4146 
> > 
> > Yes, but doesn't the diacom package contain some kind of interface box? I
> > know GM PCMs use a weird speed, 8192. 
> >
>   Well, it acutally hooks up to the parallel port.  And the instructions
> imply that the software has to initialize the hardware molded into the
> specialized cable.  Have not gotten around to look at what goes in and 
> out of this cable yet, since I no longer need to home-brew an ALDL interface.
> The only reason I can think of for there to be hardware in the cable is
> so that my 4.77 MHZ laptop can still read in 8192 baud data.  I imagine
> a faster computer can just pole the parallel port and read in the data
> that way.

Could you please explain more about this. I'm no wizard when it comes to
parallel ports. What is meant by poling the port? And how do they adapt
the parallel port to a serial interface? I bet the cable could be duplicated
for a few bucks, and if someone can explain what it does, I'd be happy to 
experiment on this.
 
Markus