AT&T (News - Alert) mobile customers in Hampton Roads, Va., have some good news and bad news when it comes to mobile phone service. The good news is that VoLTE and high-definition voice (HD voice) are available in the area. The bad news is that, unless both parties on a phone call are using VoLTE-capable phones and both are on an AT&T VoLTE network at the time of the call, the call will not be able to use VoLTE/HD voice.
Back in May, AT&T initially rolled out its VoLTE/HD voice service to a few markets in Illinois, Indiana, Minnesota and Wisconsin and the only device you could use it on was a Samsung (News - Alert) S4 Mini. At that time, the only other carrier to offer such service was T-Mobile and service was only available in Seattle.
Since then, both the number of supported devices and coverage areas have grown. Soon, users from different carriers will be able to make VoLTE/HD voice calls to each other. According to PC Magazine, AT&T and Verizon, the two largest mobile phone service providers in the U.S., are working on having interoperability between the two networks sometime in 2015.
Technical obstacles have stood in the way of carrier interoperability arriving sooner. AT&T and T-Mobile are GSM networks, while Verizon, Sprint and U.S. Cellular (News - Alert) are CDMA networks. GSM and CDMA handle the process of putting calls and connections into the same radio channel differently, making them incompatible. Additional work is needed for AT&T to interoperate with Verizon (News - Alert) on VoLTE/HD voice calls.
So for the time being, the technology is limited to the point that many users may not be able to take advantage of it too often. Most likely, families or businesses with multiple supported phones on the same account where the users called each other from VoLTE-enabled cities might put the technology to use, but the rest of us will have to wait for probably another year. When VoLTE/HD voice is available on a widespread basis, however, it will truly be a breakthrough.
Edited by Alisen Downey