Subdivision of 6.2.1.1 RTT communications in testable cases
6.2.1.1 is currently very broad. It would benefit from being subdivided in different situations. Annex C clauses should be authored along with the test methods requested by the EAA in its preamble (79) referring to ‘Module A’, set out in Annex II to Decision No 768/2008/EC.
Here is a proposal for replacement of 6.2.1.1.
Test clauses for C.6.2.1.1 are proposed in Issue #211
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6.2.1.1 RTT communication
6.2.1.1.1 RTT communication in general
Where ICT is in a mode that provides a means for two-way voice communication with other ICT, the ICT shall provide a means for two-way RTT communications with the same other ICT and in at least but not limited to the different situations specified in clause 6.2.1.1.2 to 6.2.1.1.8 in which two-way voice communications is provided, except where this would require design changes to add input or output hardware to the ICT.
NOTE 1: This requirement includes those products which do not have physical display or text entry capabilities but have the capability to connect to devices that do have such capabilities. It also includes intermediate ICT between the endpoints of the communication.
NOTE 2: There is no requirement to add: a hardware display, a hardware keyboard, or hardware to support the ability to connect to a display or keyboard, wired or wirelessly, if this hardware would not normally be provided.
NOTE 3: The following examples provide information on how RTT is specified in various technologies. The standards and specifications commonly provide both accessibility requirements and technical solutions. The information in this note reflects the situation at the time of authoring the present document and can be used for planning end-to-end functionality both within and between technologies.
-Presentation-
ITU-T has published a standard for coding and presentation of RTT, in Recommendation ITU-T T.140 [i.36] .It is used by all technologies below.
General VoIP and Multimedia calling. IETF, providing standards for Voice Over IP (VOIP) and Multimedia calls over IP based on the Session Initiation Protocol (SIP), has published IETF RFC 4103 [i.13] for session establishment and transport of RTT and its update RFC 9071 for multiparty use [i.rfc9071] .
-Mobile Multimedia Telephony.-
3GPP, providing standards for mobile communication systems, including IP Multimedia Sub-System (IMS) has standardised the Multimedia Telephony concept, for calls with voice, video and RTT using the set of protocols specified in 3GPP TS 26.114 (= ETSI TS 126 114) [i.10] to create the services including RTT and Total Conversation services specified in TS 22.173 (=ETSI TS 122 173) [i.11]. Multimedia Telephony is specified to use IETF RFC 4103 [i.13] for session establishment and transport of RTT . Mobile product profiles. GSMA, providing selected profiles of standards for implementing globally interoperating mobile communications services has in NG.114 [i.ng114] specified how to apply TS 126 114 to implement Voice over LTE (VoLTE) and Video over LTE (ViLTE). RTT is specified in NG.114 Annex B.2 to use IETF RFC 4103 [i.13] for session establishment and transport of RTT..
-Web technologies.-
For communication in Web Technologies, W3C and IETF have created the WebRTC concept [i.rfc8825]. IETF has published RFC 8865 [i.rfc8865] for implementation of RTT in web technologies using the WebRTC Data channel concept.
-Circuit switched technologies.-
For communication in circuit switched PSTN technologies, a number of modem based technologies for RTT-like communication have been in use, collectively specified including procedures for communication between them in Recommendation ITU-T V.18 [i.23]. The functionality of communication between PSTN text telephony according to V.18 and RTT cannot fulfill all RTT requirements in the present document. They all have limitations in for example speed, simultaneity, character set and multiparty presentation. Recommendation ITU-T V.18 [i.23] or an applicable annex thereof can be used for provision of functionally limited communication with RTT.
-Emergency communications.-
ETSI has published standards for IP based emergency communications in TS 103 479 [i.103479], specifying use of RFC 4103 [i.13] for RTT. This standard has a lot in common with corresponding standards for North America specified by the North American Emergency Number Association (NENA).
-Emergency apps-
ETSI has published standards for emergency apps, in TS 103 478 [i.ts103478], where RTT use is specified in TS 103 871 [i.ts103871], using Recommendation ITU-T T.140 [i.t140] for coding and presentation as all other RTT standards referenced in this clause.
-Relay services-
ETSI has published a standard for relay services in ES 202 975 [i.es202975], specifying the need for interoperability in call control and media between relay services and interpersonal communications services and devices.
NOTE 4: Where multiple technologies are used to provide voice communication, multiple communications mechanisms may be needed to ensure that all users are able to use RTT.
6.2.1.1.2 RTT communications between equipment of the same kind
Where ICT is end user equipment used for electronic communications services that provide voice communication with other parties having the same type of end user equipment served by the same service provider, the ICT shall provide RTT communications with the same other parties except when this would require adding of text input hardware or presentation hardware.
6.2.1.1.3 RTT communications between different kinds of devices within the same service
Where ICT is end user equipment used for electronic communications services that provide voice communication with other parties served by the same service provider and using another kind of device, the ICT shall provide RTT communication with the same other parties except when this would require adding of text input hardware or presentation hardware.
6.2.1.1.4 RTT communications between services
Where ICT is an electronic communications service providing voice communications with users in other services, the service shall provide RTT communication with the same other users except when this would require adding of text input hardware or presentation hardware.
6.2.1.1.5 RTT communications in roaming conditions
Where ICT is a service providing roaming for its user terminals to other services, a user terminal roaming in another service being provided with voice communication with users in the home service shall be provided with RTT communications with the same users except when this would require adding of text input hardware or presentation hardware.
6.2.1.1.6 RTT communications between technologies
Where ICT provides two-way voice communications with other ICT, and they use different technologies for RTT communication with end user terminals, the ICT shall provide RTT communication between the same ICT except when this would require adding of text input hardware or presentation hardware.
6.2.1.1.7 Emergency communication by RTT
Where ICT provides two-way voice emergency communications, the ICT shall provide RTT emergency communications except when this would require adding of text input hardware or presentation hardware. NOTE: The topic of access to emergency communications is covered in clause 13.
6.2.1.1.8 Relay service access by RTT
Where ICT provides RTT communications, the ICT shall provide RTT communications with relay services except when this would require adding of text input hardware or presentation hardware. NOTE: The topic of access to relay services is covered in clause 13.
Definitions:
RTT test terminal: a terminal provided to be a terminal to perform tests of the ICT under test against. It may be a normal human operated production terminal or a terminal integrated in a test environment offering remote control and observation with logging of the test terminal in a way with minimal influence on the performance of the terminal.
*Test clauses for C 6.2.1.1.x are proposed in issue #211