Why does volte need text messages?

It's safer, it's the owner, and it can be proved that it's voluntary.

China Unicom app-enter "volte" through the top search bar-open it immediately (or China Unicom app-handle-basic business handle-volte HD call);

Unicom online business hall-handling-basic business handling -VoLTE HD call;

SMS: Enabled: Edit "DGVOLTE" and send it to10010; Cancel: edit "TDVOLTE" and send it to 100 10.

VoLTE is Voice over LTE, that is, voice call under 4G network. It is an IP data transmission technology, which does not need 2G/3G, and all services are carried on 4G network, which can realize the unification of data and voice services under the same network.

In other words, 4G networks not only provide high-speed data services, but also provide high-quality audio and video calls, all of which require VoLTE technology.