I have devices that will do this - these are actually RS-232 data switches
that I designed in the 80s. It was a whole line ranging in size from 8 to 56
In fornt of me i have something called a 'NetCommander' made by 'Digitial
Products In (the SUB-LAN Company)'. It's got 16 RS232 ports, and you can
tell it to 'connect' any port to any other port with different baud rates
on the 2 sides. The Rs232 ports are on plug-in cards (2 ports to a card),
so I guess parallel cards also existed. I do have a smaller one, all on
one baord, with 6 RS232 ports and 4 parallel ports IIRC.
Never done much with it, maybe I should...
-tony