5starfone

It uses SIP protocol based for signaling.
Supports G729,PCMU, 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.
Compatible with all sip standard switches.
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 dialer more efficient in making VoIP calls.
Integrates with mobiles phonebook and auto detects (+) sign when contact is picked from phonebook.