Verizon pledges interoperability for its RTT technology deployment

Verizon (NYSE: VZ) revealed a little bit more about its plans for IP-enabled wireless services for the hearing impaired, telling the FCC that it has implemented industry standards that will support interoperable real-time text solutions.

Verizon says it is determined to develop and deploy real-time text (RTT) technology that will be interoperable with other RTT services and applications and that users may continue to rely on the older text telephony (TTY) technology in the future. Included in its LTE network is support for the Internet Engineering Task Force (IETF) standard RFC 4103, which AT&T (NYSE: T) also has said it is planning to use in development of RTT.

While Verizon will build on its existing implementation of RFC 4103 and related standards to support RTT transmissions, it also said that its initial testing, which is still preliminary, included successful TTY calls between VoLTE devices with external TTY devices attached. Beyond the initial tests and before making it commercially available, Verizon plans to conduct "additional batteries of formalized, systematic tests" to ensure that TTY and RTT signals are transported successfully within its network, as well as between Verizon's network and other provider networks.

"This includes the complex 'interworking' capabilities that enable functional communications between RTT and TTY, thus allowing the newer RTT technology to work with the existing base of TTY devices in the market," the company said in its report to the FCC.

In granting Verizon a temporary waiver last November, the FCC said that in addition to conditions that it had imposed on AT&T when it got its waiver, the FCC wanted to see a preliminary report from Verizon that described with greater specificity how it plans to meet its commitment to deploy RTT. Verizon's Feb. 11 filing was in response to that requirement.

Verizon said it's also working to confirm that critical features and capabilities inherent in TTY can be implemented in RTT, including the ability to ensure "hearing carry over and voice carry over operate smoothly" in connection with new RTT capabilities. It's working with device manufacturers to identify potential issues and opportunities, and it has assembled a cross-functional team to develop its solution.

The team, which includes engineers and business managers, is focused on the wireless network, wireless devices, emergency calling capabilities and accessibility. It meets at least weekly to address issues as they arise. Verizon expects to complete development and testing of RTT technology by the end of 2017 and promises to make sure that interoperable RTT services will reliably function with new IP-based wireless networks.

Cellular South also received a waiver for rules requiring support for TTY technology and the FCC last month clarified how the carrier must notify its customers that TTY technology will not be supported for calls to 911 services over IP-based wireless services. Because Cellular South won't begin deploying IP-based wireless calling until the summer of 2016, the FCC said it can wait until it's closer to that time before it is required to send out notices.

AT&T was the first operator to ask for a waiver related to TTY. It wanted to launch Wi-Fi calling on Sept. 25 but was delayed due to its pending waiver request, which it said gave T-Mobile and Sprint an unfair advantage as they were providing Wi-Fi calling "in defiance of the Commission's rules." AT&T ultimately launched Wi-Fi calling on some devices in early October.

RTT is designed to work on IP-based networks and is generally viewed as preferable over the older TTY technology. People who are deaf or hard of hearing began using TTY technology in the 1970s as the only means to send and receive text communications over a telephone network. RTT transmits text instantly, allowing each text character to appear on the receiving device at roughly the same time it is being typed.

Some consumers with communications disabilities still rely on TTY, so there's been concern about making sure they're covered. However, in granting AT&T's waiver request, the FCC also pointed out that a 2013 survey by the Rehabilitation Engineering Research Center on Wireless Access found that only 2 percent of respondents who were deaf, 1 percent of respondents with a speech disability and zero percent of respondents who were hard of hearing had used mobile TTY to contact emergency services.

For more:
- see this Verizon filing

Related articles:
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Verizon gets temporary waiver on TTY technology for VoIP calls
Verizon accepts FCC's invitation, seeks TTY waiver for VoIP calls
Verizon enables Wi-Fi calling on Apple iPhone through Verizon Messages app

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