Ground test pad to VCC pin on teensy, VCC test pad to ground pin on teensy, test pad to test pad, and pin to pin, doesn't matter, all register at 1.5V.
For ****s and grins, I tried going off the other ground and VCC pins on the teensy, and all works now!
Just to let you know that this works, I am typing this from the XT now, and will be taking it with me to work.
I really forgot about the different thwack sound of the F verses the M. Really been a long time since I had a chance to use one of these. I am really happy considering that I will be having some marathon sessions at work this week because of the final portion of the data center migration, so I am happy that I have this keyboard going. Right now on OSX, so no arrow keys since I cannot disable the numlock, but oh well. I have the keyboard working and that is what matters. That's a problem of the OS and not the keyboard or convertor, and could be overcome with changing the key mapping if I really want to, but probably won't monkey with since this is going to be used on Linux and Windows.