Does anyone know if rs-232 c++ code written with the windows.h library is easily changed to support rs-485 and rs-422 or if its not similar at all? Thanks.

depends. If the code uses normal win32 api functions such as CreateFile() to open the com port, then you shouldn't have to change a thing. The device driver will make it transparent to your program.

excellent, I am, thats what I needed to know. Thanks.