Last week, we told you how AT&T felt that it had been treated unfairly by the FCC. While the carrier decided to play by the rules and wait for an FCC waiver before offering Wi-Fi calling, Sprint and T-Mobile went ahead without a waiver, and started offering the service to its customers. AT&T filed a waiver in June, requesting that they be allowed to proceed with Wi-Fi calling without offering TTY service over Wi-Fi. This is a teletype service used by the hearing impaired to type out phone calls to each other. AT&T is working on a replacement service called RTT (real-time text).

Yesterday, we told you that the FCC had finally granted the requested waiver to AT&T, allowing it to begin Wi-Fi calling service. And today, the nation’s second largest carrier announced that Wi-Fi calling is now available for the Apple iPhone 6, Apple iPhone 6 Plus, Apple iPhone 6s and Apple iPhone 6s Plus, as long as they are running on iOS 9.

To use Wi-Fi calling on your eligible iPhone, go to Settings > Phone > Wi-Fi Calling > Wi-Fi Calling on This Phone (Toggle on). Once the service is enabled, it will allow you to use make calls over a Wi-Fi connection, even in a weak cell area.

source: CNET (1), (2)