I am using Digi PortServer TS MEI in modem emulation mode, to encapsulate PPP session over Ethernet.
In my system, at one end of the line I have a PPP-capable device + the PortServer TS, and on the other end I have a Windows box + another PortServer TS. The Windows box is configured to accept dial-in requests, and to dial-out on demand. Now, it is a waste of hardware to have that second PortServer TS attached to the Windows box. Is there by chance a sort of "software modem", i.e. an application that encapsulates the telnet session, implements all AT commands as expected, and shows up in Windows as another COM port with attached modem?