I am posting my welcome wagon post required for new members.
I'm Bill. I worked for a small company in Buffalo MN, USA from 1984-1988 designing hardware and software for traffic controllers for a small company called Minnesota Microtronics. We had replacement controllers that I was never involved with, but I know the details of the design of the Model 800, and other "newer" controllers of that era.
I miss the control industry and the website peaked my interest.