I want to make a windows application in which I want to send ,receive and process SMS using GSM Modem( this one ), It would be very helpful If you provide me link to any opensource library or application which do the same. I am good in MFC and Qt, so any C++ or C library or app reference would be much better.
It would be great help, If you can tell me/Give some reference of how to do incoming call processing. I want to read user's keyboard input during call ( Like press 1 for Apple and press 2 for Microsoft ). As in next version I want to support this.
For the SMS part you can use the open source Kannel server. It will work with GSM modems and provide an interface (HTTP) for your application to interact with it.
Call wise, you are probably looking for an IVR solution. You can write the branching logic (voice menu, press 1 etc) in its language. Asterisk seems to support that but I have no experience with it.