It looks like it will be up to the FCC to determine when AT&T (NYSE: T) will commercially offer Wi-Fi calling through Apple's (NASDAQ: AAPL) iOS 9. The iOS 9 update, which Apple says is on pace to be downloaded by more users than any other software release in the company's history, added a Wi-Fi calling option to AT&T's version of the iPhone, but AT&T is still waiting for the FCC to grant a waiver so it can use real-time text (RTT) instead of TTY.

Instead of the old-fashioned TTY, AT&T says the FCC should recognize RTT as an alternative accessibility solution for the deaf and hard of hearing. In a petition filed earlier this year to get the rules changed, AT&T explained that it wants to deploy RTT because TTY is obsolete, offers inferior functionality and features and doesn't operate reliably on newer voice over Internet protocol (VoIP) platforms.



AT&T says that while customers who enrolled in Wi-Fi calling through the iOS 9 beta will still be able to use it, no new users will be enrolled. Those already enrolled will receive a text message that notifies them of the beta's completion and prompts them to update their E911 address again. "AT&T tested Wi-Fi calling through the iOS 9 beta and we are prepared to support commercial launch of the service once approved by the FCC," the company said in a statement first reported by Phonescoop.

T-Mobile US (NYSE:TMUS), which has supported Wi-Fi calling since 2007, appears to address the issue by using Rich Communications Services (RCS), which the GSMA started promoting back in the 2008 timeframe as a way to counter act the over-the-top (OTT) crowd.

"T-Mobile supports the growth of services that include letter-by-letter transcription, but does not believe real time text (RTT) is required for Wi-Fi Calling, which we have offered since 2007," the company said in a statement to FierceWirelessTech. "T-Mobile's Advanced Messaging provides near real-time text and chat right out of the box and is a huge advance in the messaging tech that comes built into most phones. As we have with technologies like HD Voice and Video Calling, T-Mobile continues to lead by becoming the first and only wireless provider in the nation in July 2015 to offer Rich Communications Services that let you see when others are typing, when your message is delivered and even read. And it is designed to work across all devices, makers, operating systems and wireless providers. All carriers, including AT&T, should embrace Rich Communications Services."

The FCC isn't saying if or when it may approve AT&T's request. As AT&T noted in its petition, T-Mobile and Sprint (NYSE: S) have deployed Wi-Fi calling while Verizon (NYSE: VZ) is transitioning to a VoLTE-only network.

Apple started supporting Wi-Fi calling in its iOS 8 operating system. With iOS 9, AT&T customers will be able to make Wi-Fi calls when it becomes available. According to an Apple support page, consumers need an iPhone with AT&T, Sprint or T-Mobile in order to place a Wi-Fi call; Verizon is not listed. Outside of the U.S., Wi-Fi calling is supported by Bell and Rogers in Canada, 3 and SmarTone in Hong Kong and EE and Vodafone in the United Kingdom.

For more:

- see this Phonescoop article

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