In 2014, Apple brought the iPhone 6 to the world and, with it, the HD voice feature, using the quality of the LTE connection to make better calls. The technology was called Come back (Voice over Long-Term Evolution).
As this type of resource depends a lot on the operators, it was to be expected that it would not arrive so soon here in Brazil – and that is what actually happened. To our delight (at least for her clients), TIM started making VoLTE available in 21 Brazilian cities (including São Paulo, Rio de Janeiro, Brasília, Fortaleza, Maceió, Recife, etc.), with a forecast of reaching more than 1,000 municipalities by the end of the year.
To take advantage of the feature, your device must be an iPhone 6 or later (including iPhone SE) and have iOS 11 installed. So, just enable the option in Settings »Cellular» Cellular Data Options »Activate 4G» Voice and Data.
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While Brazil is adapting just now to a technology from three years ago, Apple launched with the new iPhones (8, 8 Plus and X) the new generation of HD voice calls: Enhanced Voice Services (EVS).
In an interview with the Engadget Japan, KDDI operator president Takashi Tanaka confirmed that the new devices support the new generation of HD voice calling. EVS allows making a connection with much higher quality and closer to real communication, using a frequency range from 50Hz to 14.4kHz (much larger than the VoLTE standard, which only goes from 50Hz to 7kHz).
For now, only the British operator EE has support for what they have called “Enhanced HD Voice” on iPhones 8/8 Plus (most likely this is the same feature, only under a new name). In the United States, as the technology has been around for a while, most likely all operators will provide support for it on new devices. It’s in Brazil? Well, who knows three more years from now?… ?