Hmm... I've never seen any of the systems like you describe, but I would
guess that the RJ45 jack is probably just standard 10Base-T Ethernet
(or if the machine is really strange, Token Ring, but I would doubt that).
If you've got a small network onhand with a machine capable of serving
BOOTP, you might want to try turning on the BOOTP server to see if
you can pick up the request from the machine (BOOTP is a rather standard
way of doing such things).. you could pick up the MAC address of the
system's Ethernet device by running a sniffer like TCPdump when it
is broadcasting looking for an IP.
_NO_ idea what this little bugger might have ran, though.. perhaps some
variety of stylus-enabled DOS/Win 3.1 or something along those lines,
i'd imagine.
-Sean Caron (root(a)diablonet.net)