I heard that Shanghai Unicom's 4G package can open high-definition voice. How to open it?

Users of the 4G package can open it directly by SMS, and send a message TDVOLTE to 100 10.

Users who support the VoLTE function have launched the VoLTE high-definition telephone service, and started the VoLTE high-definition call under the "Mobile Network" project in the mobile phone setting interface. When the user's mobile phone is in the coverage area of Unicom's 4G network and VoLTE, after the mobile phone logs into VoLTE successfully, it can dial VoLTE HD phone, switch voice and video at any time, and surf the Internet synchronously. Namely: turn on VoLTE-turn on the VoLTE function on the mobile phone-make a VoLTE HD call-switch voice/video-synchronize the Internet.

Note: Use the VolTE service phone to display the "VolTE" or "HD" icon.

To use VoLTE high-definition telephone, both parties need to support and open VoLTE high-definition telephone service.

VoLTE high-definition voice phone and high-definition video phone service should be used to ensure that the user's mobile phone Internet package service is effective and the Internet access function is normal. If the Internet access function is turned off, VoLTE HD voice phone and HD video phone service cannot be used.