How to close Unicom's oppo mobile phone HD?

The "VoLTE HD Call" function belongs to the business scope of operators (China Mobile, China Unicom and China Telecom). After the operator opens and successfully registers the "VoLTE HD Call" function, the word "HD" will be displayed in the status bar of the mobile phone. VoLTE setting method:

ColorOS 7 and above: "Settings > SIM card and traffic management >: Select a SIM card > VoLTE HD call".

ColorOS 3.2-6. 1 Version: "Settings >; Dual card and mobile network > select SIM card > VoLTE call ".

Remarks:

1, OPPO models use telecom cards to turn on the VoLTE switch by default, and mobile phones cannot turn off this switch.

2.OPPO 5G models use Unicom cards. If the 5G switch is turned on, the phone will turn on the VoLTE switch by default. If VoLTE needs to be turned off, the 5G switch must be turned off first.

3. VoLTE switch cannot be set during the call.

4. After 4.VoLTE is turned on and registered successfully, the word "HD" will be displayed in the notification bar of the mobile phone.