CallYalla

CallYalla is a Mobile VoIP application that allows to make VoIP calls from any of the Android devices and it uses 3G/Edge/Wi-Fi Internet connectivity.

Features :-
CallYalla uses SIP protocol based for signaling.
Supports G729, PCMU, PCMA codecs.
User Friendly Interface.
Auto Sync of Balance.
Call History.
Available minutes in dialer and calling screen
Address book integration.
It has very efficient implementation of jitter buffer to play voice smoothly.
Silent suppression and comfort noise generation has been used to reduce the bandwidth usage, and this makes the application more efficient in making VoIP calls.
Integrates with mobiles phonebook.