Project Chooser

Hello!
How can I develop an application that will work on USSD code. Example of USSD code are 22554,6695. This is commonly used through mobil phone.eg send 22 to 22554 and the application will do the needful.
What should be my project chooser for this kind of project and how do I know if the program is working at run time? Did xojo has such platform?