I was looking at the schematic and realized that I could rearrange the components on my original Mark I interface ( http://www.fiero.nl/forum/Archives/Archive-000002/HTML/20040223-1-030973.html ) and add a switch to switch the ECM between various modes. Here's the schematic I drew, sorry for the crudeness of it:
The transister is a 2N2222, a very generic that has lots of substitutes. .
I used the same process as I detailed in the previous model, so I won't go into detail here beyond the finished product:
One of the advantages of doing it this way is that I cut the part count inside the DB9 connector down to one resistor, making it much easier to finish that end of the cable. The other end was easy to make as well, and if I get some time between now and Wheatstock I'll make up some more for anyone that wants one.
Now all I have to do is figure out how to make a nice case for the ALDL end...