1) User friendly interface
2) Dialer supports SIP for signaling.
3) Dialer supports G729, [url removed, login to view], G723.1, iLBC codec for sending audio & Video data.
4) Dialer should be able to run behind NAT or on private IP.
5) client can see the remaining balance in real time.
6) Dialer should be fully customizable.
7) Dialer with any kind of Soft switch which support SIP (SER/OpenSER/Asterisk)
8) Mobile SIP dialer for OS Mobile: Symbian (ALL), iPhone & iPod, Windows, Android OS, (communication via either GPRS, EDGE, 3G or Wi-Fi
connection), Voice & Video
9) Full source code must be provided with proper comments on the code.