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MobiSIP Pro

Official Description

* VoIP Calling Support
* Calling Card Support
* Multiple Codec support with G.729 Codec Support.
* Call Recoding
* TLS/TCP/UDP Support
* SRTP Support
* Custom Place Holder Text
* Callerid Support
* Call History Support.
* DTMF Support
* Support Calling over 3G and WiFi
* Speaker phone, Mute and Hold functions
* Excellent audio quality
* Balance display (with Currency) on Main Screen.
* Contact Picker tab for selecting contacts from Phonebook.
* In-coming Call Support


Know more: http://mobisnow.com/app/android-sip-dialer/

IMPORTANT: Its a standalone VoIP client software for android Smart Phones, to make and receive calls using MobiSIP, you must subscribe to any SIP Service provider.