I want to know more!
I assumed numbers were entered directly on a 10-key. Were they scantrons as a paper record, as an asynchronous way to enter the data, or?
Also--we didn't use a 10-key! Our keypad was 2x5 rather than 3x3, and inverted (low numbers at the top).
for the uninitiated https://www.youtube.com/watch?v=RT4__Nz5HWY