I want to run an old TRS-80 Model 4 BBS program in an emulator (xtrs). The Model 4 only has 1 serial port and by default the emulator links this to /dev/ttyS0 but that can be changed to anything via a command line switch.

I'd like to be able to telnet (no, don't want ssh) to the linux box that is running the emulator and have that telnet session passed through something and on to the BBS in the emulator.

In the later days of DOS and early days of Windows this would have been accomplished with a Fossil driver. The DOS box (for example) would be networked and accept telnet connections. The Fossil driver would get that connection and pass it to the BBS by emulating a modem. The BBS would communicate back not knowing it wasn't talking to a real modem.

While I haven't found anything similar for Linux I figure there must be a way to do this with tools such as modemu. Modemu works kind of like this but is designed to allow comms programs (such as Minicom) to telnet out. It doesn't seem to be designed to accept telnet connections. It can work with pts masters/slave but I don't know enough about that.

So again, the chain would be:

incoming telnet->"fossil driver"->BBS connected to any /dev

In the past I've used mgetty for sort of the reverse. But I don't see how that could be used here. Any ideas , suggestions or solutions?