Just two days after the Federal Communications Commission granted AT&T a waiver, the wireless provider is making Wi-Fi smartphone calls available to cellular customers.

AT&T customers with an iPhone 6, iPhone 6+, iPhone 6S and iPhone 6S+ models can today begin using Wi-Fi for calls in addition to using the traditional cellular network in the U.S. They need to have iOS 9 installed and have a postpaid wireless account set-up for HD Voice and a Wi-Fi Internet connection at home or in the office.

“Wi-Fi Calling is a complement to AT&T’s already great network coverage,” said AT&T’s president of technology operations Bill Smith in a blog post. “Along with a network that covers more than 99 percent of all Americans, our customers now have an option for making calls in areas where a cellular signal is tough to get – such as a home or office with dense building construction.”

The FCC’s waiver, which expires at the end of 2017, lets AT&T do something that competitors T-Mobile and Sprint have already been offering.

In other action, AT&T and Sprint aim to swap spectrum holdings in some markets across the U.S. to enable each to build larger swath of continuous spectrum for increased speed and capacity. The deal, first reported by FierceWireless.com, awaits FCC approval.

Follow Mike Snider on Twitter: @MikeSnider

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