ITIC - maintaining EN 301 549 conventions in addressing RTT interoperability
EN 301 549 is almost entirely technology neutral; the notable exception is clause 6.2.3 Interoperability, under Real-Time Text (RTT) functionality, which mandates implementation of specific standards. While interoperability is equally as important for other EN requirements (for example, 6.1 Audio Bandwidth for Speech and 8.2.2 Magnetic Coupling), these clauses do not mandate particular solutions but instead mention via Notes standards that may contribute to achieving interoperability. The RTT section of EN 301 549 should follow the convention used in other parts of the standard and be technology neutral, stating what needs to be done but not how to do it. Specifically:
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Clause 6.2.3 should be removed from the standard.
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Clause 6.2.1.1 RTT communication, which requires interoperability (as stated in Clause 6.2.3), should be modified as follows:
a. Add to NOTE 3 “Other standards such as Recommendation ITU-T V.18 [i.23], IETF RFC 4103 [i.13], ETSI TS 126 114 [i.10], ETSI TS 122 173 [i.11] and ETSI TS 134 229 [i.12] may be useful to achieve interoperability.”
b. In addition, create a new Note as follows:
"NOTE 4: Where multiple technologies are used to provide voice communication, multiple interoperability mechanisms
maycan be needed to ensure that all users are able to use RTT.EXAMPLE: A conferencing system that supports voice communication through an internet connection might provide RTT over an internet connection using a proprietary RTT method. However, regardless of whether the RTT method is proprietary or non-proprietary, if the conferencing system also offers telephony communication it will also need to ensure that RTT is supported over the telephony connection."