This is a bit of an unusual connection style. Any ideas how to achieve it? I think I'm suffering tunnel vision, and I could use a few clues to help expand my vision.
At the remote site is a modem-like device. The remote site uses DHCP addressing, and NAT to get to the Internet, so I'm thinking that the remote site would use telnet-to-a-high-port to reach the server... likely a 1- or 2-port console server, triggering off the DTR to establish a connection to a known destination automatically.
local modem console server? (auto-telnet to IPaddr:port)
At the IP address (the server), preferably a Linux machine, the TCP listener would present as a local TTY. No exec/login function. A local application would use the TTY port as though it was a locally-attached serial port or USB serial dongle.
Best regards,
-Z-