On Nov 23, 10:49*am, Hoosierpopi wrote:

... . If I could find a router with an RS-232C port, I might be
able to network both computers to the same dial-up connection

Not just an RS-232C port, go for one with a builtin modem.
The graphite and snow Airport models (Apple made them
compatible with Windows as well as MacOS setup tools),
and Lucent/Orinoco early routers had Ethernet, WiFi, and
modems builtin. Used ones can't be too pricey; Apple
model numbers are M8440, M5757, and some (not all) A1034;
Lucent model RG-1000.