Was not a TUI, but was totally controllable from the keyboard. There was no mouse or touch screen, you could get pretty fast at it. You are also correct about the tax exempt thing, the customers who used it often knew what to ask for. The new registers now have a completely different UI with a touch screen. Seems like a step backwards.
Giving someone a sequence of keypresses as instructions rather than a series of obscure buttons and submenus to navigate is so much better. The VI/VIM cultists have been wise to this for over 30 years yet we insist on creating terrible mini-pc's running bloated windows to hark up a hodge-podge of WinForms or whatever proprietary corpo-slop is most friendly for the non-software engineer engineering manager and project lead
