Real-time text with audio, video can replace AT&T's TTY service, joint study says

A study by Gallaudet University in Washington, D.C., the University of Wisconsin-Madison and Sweden's Omnitor into real-time text (RTT) concludes that RTT together with audio and video in smartphones with additional alerting features is the way to go for accessible electronic communication.

RTT is the technology that AT&T (NYSE: T) wants to use to replace the outdated teletypewriter (TTY) technology used by the deaf and hard of hearing. TTY doesn't render well for IP communications. AT&T asked for and received a temporary waiver from the FCC's TTY rules in order to offer Wi-Fi calling on certain devices. AT&T argued to the commission that approving its waiver would signal to the industry that RTT is a permissible alternative to TTY and that it better serves the needs of disabled communities.

Verizon (NYSE: VZ) also plans to deploy RTT as a successor technology to TTY. The FCC granted Verizon a waiver similar to the one it gave AT&T but it stipulated that Verizon needed to provide more specificity about its plans for meeting its commitment to develop and deploy RTT or an alternative text-based solution accessible and interoperable with other carriers' solutions and with backward compatibility with TTY.

The Gallaudet study notes that RTT is often combined with audio and video in a multimedia call offering the benefit of using all media that are of value for real-time communications. A field trial was performed in 2015 by the Rehabilitation Engineering Research Center on Telecommunication Access (RERC-TA) partners in Sweden and the United States. Forty-nine participants were involved, including people who were deaf, hard of hearing and friends and relatives of the deaf or hard-of-hearing participants.

The findings of the trial were consistent with prior research. The main conclusion is that RTT is preferred over messaging for conversational situations. RFC 4103 is the most widely cited standard for RTT and should be used in SIP and IMS technologies, the report said. For environments where RFC 4103 does not fit, conversion to RFC 4103 should be supported wherever they interface with SIM or IMS, the report added.

RTT is a mode of text communication where the text is sent immediately while it is typed, so that the receiver gets an opportunity to follow the thoughts of the sender as they are formed into words. Functionally, it's akin to voice calls where the receiver also follows the words of the sender the moment they are formed or spoken, the report notes. RTT contrasts with the messaging mode in that text in messaging is collected by a sender and then sent in full only after the sender has finished composing the message in its entirety.

Ninety-six percent of participants agreed on the importance of being able to interconnect TTY and the IP-based RTT conversation, the most common rationales being the desire not to leave TTY users behind and to allow accessibility for people who are deaf or hard of hearing in rural areas. All participants affirmed the importance of being able to call between different technologies, including TTY, IP and WebRTC environments.

The technologies used by AT&T for a series of demonstrations in May 2015 used RFC 4103 for real-time text and an RFC-4103-RTT to TTY gateway for conversion of text communication in calls between RTT users and TTY users. AT&T has proposed that RFC 4103 be used in IP-based wireless services and pledged to deploy RFC 4103 throughout its networks by 2017, the report notes.

RTT has been standardized for many years and real-time communication with voice, video and text based on web browser technology is in active development under the name WebRTC.

For more:
- see this report

Related articles:
Verizon gets temporary waiver on TTY technology for VoIP calls
AT&T gets waiver from FCC, will move ahead with Wi-Fi calling launch
AT&T explains delay on iOS 9 and Wi-Fi calling
AT&T still aims to launch Wi-Fi calling in 2015

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