AT&T is shutting down its 3G network. Here's how it could impact you

Twenty years after 3G was first introduced in the United States, paving the way for a new generation of mobile apps, the network is officially being phased out.

AT&T is set to pull the plug on its 3G network Tuesday, with other major US carriers expected to follow suit later this year. The move impacts everything from older phones to home alarm systems and roadside assistance systems.