Why?The final goal is actually do use the line simulator I have here and dial out/in locally.
Why?
(just curious)
I don't quite get where the line simulator fits in, but is this at all relevant:
http://www.jammingsignal.com/leif/bbs/
Ignore the C64 bias, and the "BBS Server" is misleading; it's basically both ends, a client that lets you connect to a Telnet BBS (or whatever) from petty well any RS-232 equipped computer, as well as the other end, a Telnet to 8-bit BBS bridge.
Read the manual to see if it's what you want.
Sounds pretty straightforward; set the second modem to auto-answer (or install an actual BBS in a VM) and away you go. Is there a problem, or you just haven't gotten a round tuit yet?
Once you connect to the other computer, then what?