Thanks for the reminder. I had thrown around a few concepts a few years back but put it on the back burner since I have so many other projects ongoing. Simply; hook up two modems on a couple of dedicated freqs as a simple LocalNet setup. Oh, you’d still have to fake the Tip, Ring, and Dialtone to get the modem functioning, but then again PBX software has been around a long time and it might be fun to play with that and get something reliable going between a group of Hams for example. At 56kB max you would not be able to quickly send a vid file, but for a general BBS or Chat setup I think it would be perfect.
Primarily for local use, some long-distance could be set up also if desired with appropriate planning.