The author mentions, “Watch out for HPIB-only plotters!” — I forgot to take that advice when I bought a plotter from a scrap shop a few years back and thought I was completely out of luck. Spent a fair amount of time googling, and I ended up building an HPIB-to-serial bridge using an Arduino to get life out of the machine. Works just fine now! I’ve been meaning to write up how that works in case anyone’s in a similar disposition.