Still waiting on my parts to arrive for the test console. In the mean time i have been trying to read up on assembly, and searching SubSim for information on adding new commands in the game.
This read was encouraging:
http://www.subsim.com/radioroom/show...&postcount=966
I'm guessing if it can be done in SH5, it can be done in SH3 & 4 also.

Key commands could be setup up to adjust the TDC inputs by keyboard, meaning i can get the a TDC input panel working.
The other interesting part was:
http://www.subsim.com/radioroom/show...&postcount=123
If i could get or find those memory addresses for SH3, then I could setup real gauges in the console that would display that information. I could also have a depth & speed gauge. To me that would be kinda kewl.
However, my main goal right now is getting the input side working. I'll tackle the gauges thing later, maybe. I don't want to get too carried away, and lose interest through frustration.
Wish my stuff was here already.