Again, most of the initial cities are in the southern US, such as Atlanta, Houston, New Orleans, Oklahoma City and AT&T's home turf of Dallas. Seven more cities are coming by early 2019, including Las Vegas, Los Angeles, San Francisco and Orlando.

Like the 5G service from its rival (and Engadget parent company) Verizon, the initial launch is more about shouting "first!" than providing a broader upgrade. In addition to the limited coverage, the first devices will likely be data-only devices like mobile hotspots. You won't see more familiar access levels until 2019, when providers can both expand their networks and offer the first wave of 5G smartphones. This is more a peek at the wireless future than a practical reality.