It should look like this after starting :
4. Now come back two times and swype right to see Telephony menu in engineering mode.- Click on IMS
- Click on USSD > Ussd Support > select ON and set
- 5. Again come to common menu (inside IMS menu)
- Select operator_code > select VoLTE_Operator_RJIL from the big list > click on set
- 6. Come back twice (to IMS menu)
- Click on Common > mncmcc check > select OFF and set
- DONE .. Now click home button, exit engineering mode and check for HD voice symbol. If you see that , try calling any number from the default dialer - Fast method is to call the customer care number 199 to check if the calls are getting connected or not.
Now everything is setup.
If your phone is not showing HDvoice symbol beside the battery icon even if the HD voice is turned ON in settings (it will be next to data sim selection), try to turn off the sim and start it back (Just go to airplane mode and come back), check.
Any questions are welcome.