Up till 4G this was done using traditional circuit-switched telephony service, but with this fourth generation the entire standard instead moved to a packet-switched version akin to Voice-over-IP ...
Phone calls over the LTE cellular data network. Voice over LTE (VoLTE) is a voice over IP (VoIP) service that uses the same IP network architecture as LTE data. Although transmitted in IP packets ...
providing advice to developers whose apps “place phone calls, for instance using services such as Voice over IP (VoIP),” as to how they become the default calling app. With that setting ...