How to make a phone call with China Mobile vol te?

The 4G HD voice service adopts VoLTE(VoiceoverLTE) technology to provide 4G HD voice and 4G HD video call. Only when the 4G card is replaced, the 4G function is turned on, the mobile phone supports VOLTE (only supported by some models), the network has coverage (available in Beijing), and the 4G HD voice function is turned on can it be used. 4G HD voice is regarded as an ordinary voice call and included in the minutes in the package. 4G video calls are charged independently, and the calling domestic (excluding Hong Kong, Macao and Taiwan) is 0.29 yuan/minute (less than 1 minute is 1 minute), and the called party is free; If the same call contains voice and video at the same time, it will be charged separately, and the traffic generated during the call will not be charged. The local editor KTVOLTE is enabled as 10086, and the editor QXVOLTE is cancelled as 10086. Send "iPhone for VoLTE" to learn how Apple phones can turn on the VoLTE function. If I have processed the communication, the service cannot be opened.