I was tasked with developing an application that would be able to tell someone their cellphone credit balance via some IVR system. I dont know where to begin. Does anyone have a knowledge of GSM who could be able to give me some directions for this project.
You should look into Asterisk AGI scripts. They allow you to do more than Asterisk API. I currently have lots of AGI scripts in Perl but it says that Java is also supported. Maybe this link will help you. Basically you will create some extended Java app which will return you current Balance. Asterisk IVR would read this value from AGI and then play it.