AT&T finally shared its stipulations for unlimited data plans Wednesday. We already knew the provider was restricting the top 5 percent of its data consumers, but this announcement marks the first time it has actually detailed what those restrictions are.

The not-so-unlimited-tariffs on AT&T's 3G HSPA+ network are capped at 3GB while 4G LTE users get an extra 2GB, the company said in an announcement (summarized below). Smartphone users with an unlimited 3G or 4G data plan:

  • You'll receive a text when your usage nears 3GB in one billing cycle.
  • If you exceed 3GB, your speeds will be reduced for the rest of that cycle.
  • The next time you exceed 3GB, your speeds will be reduced sans warning.
  • Folks with a 4G LTE unlimited plan are soft capped at 5GB instead of 3GB.

AT&T says the changes are required due to ever-increasing mobile data usage and the availability of the wireless spectrum becoming scarcer. The caps purportedly ensure the best possible mobile broadband experience for all users.

The caps are unlikely to affect 95 percent of AT&T users, while the remaining 5 percent will still be able to consume data beyond the soft caps – albeit slower than usual.