If I plug this hypothetical "just works"
serial-to-Ethernet box onto
a serial port on an old computer, and plug the ethernet into the
switch along with my desktop computer, laptop, and wireless router,
what exactly should the box do? And what should I, as the user, do?
RCPMs used a version of XMODEM which worked over the same port as the
console. You would tpye xmodem s/r (send or recieve) and a file name.
XMODEM would then use the console port to upload and download the file.
You would need a xmodem version for the pc which would support a common
protocol.