b377,
Thanks for your childish belief in "software".
Even today with the glass cockpit, where do you think the R/A unit software (or whatever calculates the offset) "finds" the right information, to know what aircraft it is in? Right. It reads a pin code.
We did it with a few resistors in the olden days, connected to those same pins.
Your red herring was the "digital delays....". No such animal in this case.
CJ