The 4G LTE network can only provide data services and cannot carry voice calls. How should we understand it?

Currently, China Unicom’s two 4G networks, TD-LTE and FDD-LTE, carry data on the LTE network and voice on the 3G network. When there is no 4G coverage area, it will automatically switch to 2G\3G network. When returning to 4G coverage, it will automatically switch to the 4G network. If there is VOLTE service, it can all be carried on the 4G network. VoLTE stands for Voice over LTE, a voice service based on 4G network. VoLTE is an IP-based data transmission technology. Unlike the current 4G model that only provides data services and calls need to be switched to 2G/3G networks, VoLTE voice calls are all carried on the 4G network. In short, the 4G network not only provides high-speed data services, but also provides high-quality audio and video calls, and high-quality audio and video calls are realized by VoLTE technology.