I'm experimenting with my PiDP-11; I think I may have my modem set up properly to accept incoming calls, but with only one phone line I'm unable to test it. If anyone with a modem is willing to help me test, send me a message off-list and I'll give you my phone number & some login details.
I'd be less surprised by folks having modems (which seem like the kind of thing that gets tossed into a box and forgotten about for a few decades until eventually uncovered by a bout of decluttering) and more surprised by people having suitable phone lines to use them.
- Dan C.