Possibly to an
Epson PX-8.
An interesting thought, but the PDF manual you linked shows the PX-8 serial
port (pp16-17) is 8-pin mini-DIN.
There was an obscure UK computer made by Psion, the MC400 or something
like that, and I sort-of remember it had an odd serial connector,
possibly a 9 pin mini-DIN. But I am not sure it ever made it across
the Pond.
-tony