Here is the technical explanation for the logic behind the free voice calls.  Jio has an only 4G capability and no 3G or 2G. Most of the existing operators have all the 2G, 3G, and 4G. The existing operators transmit voice over 2G and 3G, whereas 4G is used only for Internet data. But on the other hand, Jio uses a technology called VoLTE where even the voice is transmitted as data packets over the 4G network. Please note this is different from mobile data which is only for mobile internet – technically this transmission of voice through 4G is called Packet switching. Means packet switching is different from Mobile data…