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Specialist Task Force 605:
RTT Conference Calling

Who we are:


Team leader:
Team Members:

What we do

The STF will investigate existing standards, specifications, and reports relating to Real-time Text (RTT) and conferencing systems as well as considering some of the usage issues experienced by users taking part in conference calls and meetings. The content of what is currently specified in EN 301 549 v.3.2.1 “Accessibility requirements for ICT products and services” will be examined to determine to what extent it addresses some of the standardisation needs. Gaps in coverage will be identified, with the aim that the STF deliverable will begin to show how those gaps can be filled.

For more details, see our Terms of Reference

Why we do it

ETSI EN 301 549 specifies that Real-time Text should be possible for telephony and voice conferencing systems that allow two-way communication between parties, including communication to emergency services dispatch operators and first responders.
However, there is an absence of standardisation regarding how RTT sessions involving multiple parties, comprising a mix of speaking and typing participants, should behave. This further extends into emergency calling, in cases where multiple parties are required to engage in urgent communications.
The information that is required to provide a completely accessible experience needs to be formalized at a user interface layer and a protocol layer.

How we do it

The STF experts will examine the potential sources described in “What we do”, discuss the implications of these sources (as captured in the evolving draft TR), and formulate potential areas for new or amended requirements that will be needed to help ensure that future updates to EN 301 549 will be suitable for multiparty RTT communication situations.
An Advocacy Workshop involving:
•    representatives of the potential RTT user community;
•    RTT service providers;
•    regulators and;
•    ICT industry representatives;
will be held. The aim is to share understandings of what is required and to examine some preliminary proposals for how the requirements of all these stakeholders can be met.


The STF will deliver a first draft version of TR 103 708: “RTT Multi-party conference calling specification”.
This technical report will define how user interfaces should display, present and communicate conference calls that involve RTT and voice participants supporting RTT over multi-party telephony VoIP calling.
The user interface specification will only be in terms of what the user interface should do. Detailed user interface implementation will always be the responsibility of the organisation providing the RTT products and services. The specifications in this report are expected to form the basis of new or amended requirements in EN 301 549 that will enable it to align with the requirements of the European Accessibility Act.
In addition, the STF will deliver progress reports to ETSI HF.

Time plan

The STF runs from March 2017 to January 2018. The following milestones have been agreed:

     Code              Task / Milestone / Deliverable                                                                                                            Target date                                     
    A  Draft #0.5 submitted to TC HF by 30/09/21
Progress Report approved by TC HF#86
    B Draft#1 submitted to TC HF  09/01/2022
    C Final Report to TC HF to be approved by TC HF  09/02/2022


How to contact us

To contact us, please send an email to the STF leader: Mike Pluke at

This information is based upon STF working assumptions.

The views expressed do not necessarily represent the position of ETSI in this context.