In the LTE devices which are supporting the call facility through the jio 4g voice only, not via the normal inbuilt call facility. I am using many such devices which only support calls over the jio 4g voice app which are the iphone 5 and the ipad mini 3 cellular. I have faces a lot of problems in calling at first, later on everything got fixed. I am now used to it. There are some advantages and disadvantages as follows-
ADVANTAGE-
It is really good in sound quality while making calls.
The video calling via this app is the best among all the video calling application like skype, messenger, whatsapp, hike etc.
DISADVANTAGE-
It always need the data to be on for working.
It needs that the app must be running in the background for calling.
Crash are seen severally while taking a call.
It needs to connect often to online from offline.