US wireless carrier T-Mobile is rolling out support for WiFi calling on all the phones the company sells. Pick up a Personal CellSpot from T-Mobile for a $25 refundable deposit and swap your phone for a model that supports the feature (or just buy one that does) and you get free calling and text-messaging while you’re within range of the 802.11ac WiFi router.
This means you don’t lose a signal when you go down to your basement, or anywhere else in the house where you might have a dead zone. You can also use WiFi calling when you’re overseas even if you don’t have roaming.
T-Mobile isn’t the only US carrier planning to offer WiFi calling. It’s just the first to roll it out at this kind of scale.
Part of the reason is that AT&T hasn’t started offering Voice over LTE (VoLTE) service yet, which means that calls can be dropped when your phone tries to hand them off from cellular to WiFi or vice versa. When AT&T begins offering VoLTE service, essentially all calls will be routed over a data network — and that means you’ll be able to start a call using your WiFi connection at home and keep talking on the same call when you leave the house.
Accoding to de la Vega, AT&T doesn’t feel an urgent need to launch its WiFi calling service because the company is comfortable with the network coverage it provides. So even though it’s coming, don’t expect AT&T to be as giddy about it as T-Mobile seems to be.