Some time last year I set up a dial-in connection for one of my retro PCs just for the fun of it.
Components used:
- Windows 2000 Advanced Server machine to act as a RAS server
- Dell USB modem hooked up to the server (any other non-winmodem will do)
- Windows 2000 Professional machine (the "client")
- ELSA Microlink 56k modem hooked up to the client (any other modem will do, obviously)
- an old Fritz!Box 7170 home router with built-in PBX functionality. Those are very popular here in Germany and can be found very cheap. Key success factor is that these things have at least two analogue phone ports that support internal calls between them.
Hooked everything up like this:
Client PC --> ELSA modem --> Fritz!Box <-- Dell modem <-- Server --> LAN --> router --> broadband internet
I found this to be the easiest way to setup a dial-in connection, mainly because the PBX setup of the Fritz!Box is really straightforward. Fiddling around with Win2k RAS services was the most time-consuming part, but there are still plenty of guides online that show how to do it.
Of course, this setup has zero advantage over just hooking up the retro PC to the LAN.