VKoll

Vkoll is the Mobile Dialer that allows to make VoIP calls from any of the android devices and Vkoll uses 3G/Edge/Wi-Fi Internet connectivity. Vkoll is developed based on the requirements of VoIP Providers business needs.
Vkoll Features:-
It uses SIP protocol based for signaling
Supports G729, PCMU, and PCMA codecs
Runs behind NAT or Private IP
User Friendly Interface
Auto Sync of Balance
Real Time Sip status messages
Call History
Address book integration
Call Recording
Automatic Call Recording
Compatible with all sip standard switches
Vkoll 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 dialer more efficient in making VoIP calls.