SIP Web Calling and VoIP on Galaxy S4
http://www.androidmobilevoip.com/2013/04/native-voip-sip-client-in-samsung.html
Samsung Galaxy S4 has inbuilt Web calling facility to make use of your VoIP to put Web calls. VoIP is an effective way to save cash in your name if you find yourself in roaming. You simply want an web to put a name with out roaming costs.
This video helps in the right way to arrange sip voip account with galaxy S4
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