Interacting with Subprocesses

[Dick Holmes]

I am attempting to write a Python program that will interact with
a (non-Python) process. The programs will run under MinGW. The
process can use stdin/stdout commands and responses and can work 
with pipes. The problem I'm having is that I can't find any
way in Python to have a continuing dialog with the process. I
have tried Popen communicate, but that protocol seems to be
limited to a single message/response pair, and the response
is not returned to the message originator until the process
terminates. Unfortunately I don't have access to the process'
source code so I can't change the communication medium.

Is there some feature that will allow me to initiate the process
and execute multiple message/response pairs between the Python
program and the process during a single execution of the process?

Thanks!

Dick