I am an official representative from Viber Media.
With the calling/ringing feature, you can now identify if your Viber call is ringing on your friend's phone.
A call will start off with "Calling…" state, which indicates that Viber is now connecting to your friend's phone.
If the status remains on "Calling...", it might be that your friend's phone is out of internet range or turned off.
In that case, your friend will receive a missed call notification.
Once the call's status changes to "Ringing...", this means that the phone is actually ringing on the other side.
For any other questions/concerns, please don't hesitate to contact us.