Text capture from a window

We have a number of PC's that hook (via an emulator) to a
mainfrom from a DOS window. This mainframe sends text to the
window.

The control program has some very primitive (SaveAs) routines
but nothing near the functionality that I want.

I want to be able to send a datastream and capture the resultant
incoming text. During the old DOS days, I would set up a null
modem using BitWise, EMP3, or something equally rediculous, but
I can't seem to find such an animal in the windows world.

1. Is this possible in C/C++/Java/whatever?
2. Is this realistically doable?
3. Does anyone know of a commercial/shareware/freeware
program that will do this?


Please note that I'm looking only for advice at this point.

Thank You