What files are mandatory to connect to ECM?

[camaro1995]

They are 2n2222a in TO-18 package. Will look if I can see brand name on them when I get home...
This is the schematic I had used
aldltopc2.jpg

[In-Tech]

Nice, shoot, I think I still have my original that I built in the early 90's somewhere, I put all the crapola inside the db9 shell. If I can find it I'll see what I did. Seems like I used the dtr pin and am sure I had no external power. Shortly after I built that, I moved on to a max233 and 7407 inverter to "clean" the signals further. That design has worked on every baud rate I have come across, even besides the gm stuff. I'll see if I can post a pic of my "retired" stuff if I can find it :)