Hi,
the Epson HX-20 handheld computer offered an interesting way to connect
it with peripheral devices. The serial port at the back of the computer
can talk to external hardware using an Epson-specific protocol for data
exchange. As this protocol is quite well documented, I wrote a little
program called "flashx20" (for FLoppy And Screen for the HX-20), which
allows to connect a normal Windows PC or notebook computer to the HX-20,
where the PC interprets the Epson serial protocol and simulates an
external display controller and four external floppy disk drives (like
e.g. the Epson TF-20).
With that, you get a big screen (the PC monitor) and disk space for
programs and data on the PC's hard disk, which can then also be used for
data and program exchange.
You can read more about it and download the program from my website at
http://members.aon.at/nkehrer/
Norbert