The 3270 terminal family had a numberpad-like matrix on the right side of the keyboard which was PF1–PF12 with the PF1–3 on the top row. It was a bit confusing

The 3270 terminal family had a numberpad-like matrix on the right side of the keyboard which was PF1–PF12 with the PF1–3 on the top row. It was a bit confusing for people who used ASCII terminals with a numeric keypad muxed in to access IBM mainframes as occasionally software would assume the 3270 arrangement of keys but the mapping for ASCII terminals used the keypad with the keypad’s 1–0 corresponding to PF1–PF10 and . and + (if I remember right) corresponding to PF11 and PF12 and there would be seemingly irrational arrangements of commands with up and down reversed.