You should give the ZipT app a try then if constant hello hello is a problem for you.
Perfect call clarity on any connection without the hello hello associated with VOIP apps like Skype and Viber etc.
Also as it is an app there is now requirement to install a sim card and you keep your own number as well.
It integrates seemlessly with your contacts list and calls to others who have the app installed are free.
It also works on highly congested networks as it data rate is only 8 kbps.
20 times less data usage than its nearest competitor.
Best of luck.
MRY Price at posting:
3.5¢ Sentiment: Sell Disclosure: Not Held