I've recently noticed that some of my phone calls have sounded noticeably clearer and better than usual, as if they were FaceTime Audio or Skype Audio calls.

That's because some of my calls are being made using my carrier's LTE data network, and even WiFi networks, rather than the conventional network that's usually used for standard phone calls. It's a feature that's generally known as "VoLTE," which stands for voice-over-LTE, but some carriers like AT&T and Verizon call it "HD Voice."

I say some phone calls above because VoLTE, or HD Voice, is not a consistent, standard feature yet, despite the fact that AT&T, Verizon, and T-Mobile started rolling out VoLTE services in 2014.

AT&T and Verizon leading the way

I've personally noticed these sharper, clearer calls because my carrier, AT&T, has been working with Verizon to be compatible with each other for VoLTE calls. That means some people with VoLTE-compatible smartphones in AT&T and Verizon's VoLTE coverage areas can enjoy better phone calls.

At the time of writing, AT&T told me that the efforts to make AT&T and Verizon fully compatible with each other for VoLTE calls is still incomplete, and work will continue into 2017. So, I guess I'm one of the lucky ones to experience AT&T and Verizon's interoperability in its early stages.

T-Mobile is lagging behind a little

T-Mobile customers, on the other hand, can only make VoLTE phone calls with other T-Mobile customers, at least for now. The company has said that it's working on interoperability with other carriers, but it's not in effect yet.

So, in essence, I have a much higher chance of making a high-quality VoLTE phone call because I have VoLTE access to AT&T and Verizon customers.

Update: T-Mobile has confirmed with me that it's working to upgrade the technology that will offer VoLTE interoperability with other carriers, and we can expect it "soon." It also said interoperable VoLTE service is partially dependent on other carriers updating their technology, as well.

You can get high-quality phone calls regardless

You can make high-quality phone calls without having to worry about what carrier you're on and all the requirements for VoLTE if you change your calling habits.

I likened VoLTE phone call quality to that of FaceTime Audio or Skype Audio, and you can use those apps, as well as a number of other apps like Facebook Messenger and Google Hangouts, to make high-quality phone calls. To make calls with those apps, you simply need to make sure that the person you're calling is using the same app.

It's about time that phone call quality gets an upgrade. It's a pretty start contrast when you have an incredibly powerful phone that can take amazing pictures and run great apps but makes poor quality phone calls.