AT&T Mobility (NYSE: T) reiterated its plans to launch a Wi-Fi calling service this year, as T-Mobile US (NYSE:TMUS) and Sprint (NYSE: S) have done, but did not say when it expects the service will go live.

Last month AT&T filed a petition with the FCC requesting a waiver from agency rules that require covered service providers to enable 911 and 711 short code dialing using a text telephone (TTY) device. AT&T also wants the FCC to issue new rules that "recognize, for the first time, real-time text (RTT) as an alternative accessibility solution to TTY."

"In its Petition, AT&T explained that it will deploy RTT because TTY is obsolete, offers inferior functionality and features, and does not operate reliably on newer Voice over Internet Protocol ('VoIP') platforms. RTT would enhance the accessibility solutions available to persons who are hearing and/or speech impaired, without sacrificing existing accessibility solutions, like TTY," the carrier said. "AT&T seeks this temporary waiver during the pendency of the rulemaking and until RTT is fully deployed to allow it to offer VoIP services that do not reliably support TTY. Grant of this waiver would further the TTY-to-RTT transition, bring the benefits of IP-based services, including voice, to the wireless marketplace, and enhance accessibility, without any reduction in current TTY support."

In the filing, AT&T notes that Verizon Wireless (NYSE: VZ) is shifting to Voice over LTE technology, that T-Mobile and Sprint "have deployed and are widely advertising Wi-Fi calling across their networks," and that "AT&T hopes to begin to offer its own Wi-Fi calling service later in 2015."

"As these VoIP technologies become the preferred platform for voice services, new solutions, such as RTT, are emerging for providing access to these services to people with disabilities," AT&T added. "RTT, which is designed to operate on IP-based networks, will be superior to TTY in every way--transmission speed, latency, reliability, features, privacy, conversation form, and ease of use."

An AT&T spokeswoman did not immediately have a comment on when the carrier might launch Wi-Fi calling.

In September 2014, Ralph de la Vega, CEO of AT&T's Mobile & Business Solutions Group, said at an investor conference that "we'll use Wi-Fi calling in 2015, but only as a complement." According to a Seeking Alpha transcript of his remarks, de la Vega said that everyone on AT&T's shared data plans have unlimited voice and that AT&T doesn't have "this burning desire for the need of coverage or for other reason to go aggressively after Wi-Fi."

Verizon Communications CFO Fran Shammo said at an investor conference last fall that he thought Verizon would have Wi-Fi calling available around "mid-year" in 2015. "It was just never a top priority for us only because we built our voice platform so extensively that there was never a need for us to tell our customers, oh, our network is not good enough, you need to default to Wi-Fi to complete your call," he said.

A Verizon spokeswoman said the carrier is still exploring Wi-Fi calling but has no definitive timetable for launching the service.

T-Mobile and Sprint, which still lag Verizon and AT&T in terms of LTE coverage but are closing the gap, have made Wi-Fi calling key elements of their service offerings.

For more:

- see this AT&T FCC filing

- see this separate AT&T FCC filing



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