What network monitoring application are you using, or are you developing your own?
I don't know of any command line dialers, and can't imagine why you would want to use one in Windows. You could probably write a batch file that would send commands to the COM port, but it wouldn't be very effective, as I'm not sure how to receive a response from the modem.
I believe that something along the lines of this would work:
print ATDT<phone number>; COM1:
pause 10
print ATDT<pager digits>; COM1:
pause 3
print ATH0 COM1:
but it has been a LONG time since I have done any serious batch programming.
You will be much better off using a voice capable modem for this purpose, though. You can use their on-board DSP to detect tones, silence and send tones.
Even better is a CTI board, like a Dialogic, Brooktrout or Natural Microsystems. They have excellent call progress tone detection, and they were designed to do what you are attempting to do with a modem.
pansophic