American carriers make things unnecessarily complicated when it comes to bringing your own unlocked device, and that's usually on purpose. Even if your phone has all the necessary hardware, unless it passes some additional "certifications" to get put on the carrier's whitelist, your perfectly capable phone won't be able to access features like voice over LTE (VoLTE) or WiFi calling. So how can you know for sure if your new phone is compatible with your carrier? For AT&T subscribers, there's an easy list you can check.

AT&T recently shared a complete list of devices that support various technologies on the network. The list is quite comprehensive and mentions not only the marketing name but also the model number of each device. Devices are grouped by manufacturer and the technologies they support. You can scan this list to find out if your phone supports HD Voice, WiFi Calling, Video Call, and/or Advanced Messaging on AT&T.

Why is it important to check this list? Besides knowing whether or not your phone will support faster 5G speeds on the network, you need to make sure your phone is listed as compatible with "HD Voice" or you won't be able to make voice calls at all next year. The reason is that AT&T is planning to shut down its 3G network in February of 2022, so all voice calls will be routed over the carrier's 4G LTE network. If your phone does not support HD Voice — AT&T's term for VoLTE — then it won't work after the 3G network shuts down. We previously published a list of devices that will work on the carrier after 3G shuts down, which you can check out here.

WiFi Calling support is also important but not critical to have unless you live in or work at an area where the 4G LTE signal is absolutely terrible. WiFi Calling, as its name implies, routes calls over your WiFi network instead of over AT&T's cell towers. The list below will not only tell you if your phone supports WiFi Calling on AT&T but also if your phone supports other key technologies. If you're only interested in whether or not your phone supports WiFi Calling, AT&T has a dedicated list you can see here.

The list also mentions a few devices that are compatible with Advanced Messaging on AT&T. Honestly, there's no reason to care about Advanced Messaging, which is AT&T's term for its RCS implementation. RCS, for those of you who don't know, is basically the successor to SMS. Advanced Messaging isn't compatible with other carriers' RCS implementations or Google's, so its availability is quite limited. If you really want to use the advanced messaging features of RCS, then I recommend you download the Google Messages app, turn on the Chat features, and tell your friends and family to do the same.

The last thing I wanted to talk about is AT&T's 5G network. 5G support on AT&T mainly relies on band n5 (850MHz), but it's also using a technology called Dynamic Spectrum Sharing (DSS) to broadcast 4G LTE and 5G on the same spectrum. If your phone supports 5G band n5 and most of AT&T's 4G LTE bands, then you should get decent speeds on the network. Your mileage may vary, though.

Is your phone not listed here or on AT&T's official list? Contact AT&T for support.