36 CFR Part 1194 - Proposed Information and Communication Technology (ICT) Standards and Guidelines NPRM - Preamble

D. Real-Time Text

In this NPRM, the Board proposes to require that ICT support RTT functionality whenever such ICT also provides real-time, two-way voice communication. This proposal represents a significant shift in approach for both the 508 Standards and the 255 Guidelines to better align with current technology. The existing 508 Standards and 255 Guidelines were published over a decade ago. At the time, TTYs were the most commonly available text-based system for communicating within a voice communication system. Since then, technology has greatly advanced. There are now, in addition to TTYs, multiple text-based means of communication available in the marketplace. This proposed revision will update the standards to reflect changes in telecommunications technology.

Section 410.6 of the proposed rule would require ICT with real-time voice communication features to also support communication through real-time text. Such ICT would be required to support RTT either within its own closed system or outside a network. For example, a closed communication system, such as within a federal agency, would be required to interoperate with either the publicly switched telephone network (PSTN) or Voice over Internet Protocol (VoIP) products or systems to support the transmission of real-time text. When ICT interoperates with VoIP products or systems using Session Initiation Protocol (SIP), the Board proposes to require the transmission of real-time text to conform to the Internet Engineering Task Force’s RFC 4103 standard for RTP Payload for Text Conversation. Where ICT interoperates with the PSTN, real-time text would be required to conform to the Telecommunications Industry Association’s TIA 825-A standard for TTY signals at the PSTN interface (also known as Baudot). RFC 4103 and TIA 825-A are final standards proposed for incorporation by reference in 508 Chapter 1 and 255 Chapter 1 (see sections E102 and C102, respectively).

Commenters to the 2011 ANPRM noted that other standards aside from RFC 4103—such as XMPP and XEP-0301—were currently in use and could be referenced as specifications for ICT interoperability with VoIP using SIP. XEP-0301 is one of several pending standards developed for use in the Extensible Messaging and Presence Protocol (XMPP). XMPP is a set of open technologies for instant messaging, multi-party chat, voice and video calls, collaboration, and generalized routing of XML data. XMPP was originally developed in the Jabber open-source community to provide an open, secure, spam-free, decentralized alternative to closed instant messaging services. XMPP differs from SIP, which is an application layer protocol used to establish, modify, and terminate multimedia sessions such as VoIP calls. Currently, both the XMPP and the SIP protocol are used in the marketplace. At this time, however, only the standard supporting the transmission of RTT over SIP (RFC 4103) is final. The standard supporting RTT over XMPP (XEP-0301) is not yet finalized.

XEP-0301, In-Band Real-time Text, is a specification for real-time text transmitted in-band over an XMPP network. It is used for text messaging. As of the date of this publication, according to the XMPP Standards Foundation, the XEP-0301 standard is under review and not yet final. XEP-0301 has many advantages: it allows transmission of real-time text with minimal delays; it supports message editing in real-time; and, it has reliable real-time text delivery. It can be used for multiple users and allows alternate optional presentations of real-time text, including split screen or other layouts. The standard also allows use within gateways to interoperate with other real-time text protocols, including RFC 4103. It allows immediate conversational text through mobile phone text messaging and mainstream instant messaging. For more information on the benefits of XEP-0301, see http://www.realjabber.org/xep/xep-0301.html.

Yet despite its potential benefits, the Board cannot incorporate XEP-0301 until it becomes a final standard. However, should the XEP-0301 standard be finalized before publication of the final rule, the Board plans to incorporate it by reference as an alternative technology to support transmission of RTT when interoperating with VoIP products or systems using XMPP. RFC 4103 would, in any event, be retained for ICT interoperating with VoIP products or systems using SIP technology.

Question 8. If the XEP-0301 standard is finalized, the Board is considering incorporating it by reference as an alternative standard for XMPP networks. We seek comment on the benefits, costs, and possible drawbacks associated with referencing this standard in addition to the RFC 4103 standard.

The European standard, EN 301 549 would allow the use of multiple standards for RTT. As discussed in 4.6, Harmonization with European Activities above, EN 301 549 lists several standards for RTT, as well as an unspecified “common specification” for RTT. The common specification must indicate a method for indicating loss of corruption of characters. The Board seeks comment on whether other standards should be incorporated by reference. The other standards are:

• ITU-T v.18, Recommendation ITU-T V.18 (2000) “Operational and interworking requirements for DCEs operating in the text telephone mode” (see EN 301 549 6.3.3(a)). This Recommendation specifies features to be incorporated in data carrier equipment intended for use in, or communicating with, text telephones primarily used by people who are deaf or hard of hearing.

• IP Multimedia Sub-System (IMS) protocols specified in TS 126 114, TS 122 173, and TS 134 229 (see EN 301 549 6.3.3(c)). ETSI TS 126 114, Universal Mobile Telecommunications System (which was referenced in the EAAC Report and Recommendation noted previously in Section IV.F.2) supports a “total communication” approach by establishing a minimum set of codecs and transport protocols that must be supported by all elements in the IMS system for video, real-time text, audio, and high definition (HD) audio. As noted previously, the Board decided not to require standards for video, audio, or HD audio in this proposed rule beyond the technical requirements set forth in proposed 410 (ICT with Two-Way Voice Communication). Both the ETSI TS 122 173 and ETSI TS 134 229 standards are still under development, and, therefore, cannot be referenced at this time.

Question 9. Are there sufficient net benefits to be derived from requiring ITU-T v.18 that the Board should reference it in addition to TIA 825-A (2003)? We are requesting that telecommunication equipment manufacturers, in particular, provide any data regarding potential costs related to complying with this standard. Are there suggestions for other standards which would result in the same level of accessibility?

Question 10. Are there net benefits to be derived from requiring more standards addressing multimedia than what we propose? The Board is requesting that telecommunication equipment manufacturers, in particular, provide any data regarding potential costs related to complying with the standards in EN 301 549 6.3.3(c). Are there suggestions for other standards which would result in the same level of accessibility?

Question 11. Is ETSI TS 122 173 or ETSI TS 134 229 sufficiently significant that the Board should consider referencing either standard when it becomes final?