Sellam writes about the IBM System/23:
I think the real trick will be determining whether or
not this has a
serial port. If not, I'll have to look into sending it out the printer
port.
Don't count on the printer port having the same pinout as anything you've
ever seen before. I suppose there's a very small chance that it might
use the same connector and pinout as a PC, but more likely not.
On the other hand, you should obviously ignore anything I have to say
about a 5322, since yesterday I was completely wrong about what kind
of computer it is. (I was foolish to expect IBM to maintain anything
like a consistent numbering scheme.)