How to turn on VOLTE

The following conditions can be referenced for vivo/iQOO series to use the VoLTE function:

1, SIM card contacts the operator to open VoLTE HD voice call service;

2. Turn on the VoLTE HD call on the mobile phone, and set the path: mobile phone settings-mobile network (dual card and mobile network)-Unicom card -VoLTE HD call-turn on option;

3. The area is covered by operator VoLTE network.