ISO/FDIS 17651-4

• Abstract:

  This document specifies the logistical and technical equipment requirements for the working environments of conference signed language interpreters. This document builds upon the existing standards on interpreters’ working environment, interpreting equipment, simultaneous interpreting delivery platforms and conference equipment ISO 17651-1, ISO 17651-2, ISO 17651-3, ISO 20109, ISO 24019 and ISO 22259.

• Status: Not Published
• ICS: 91.040.10 - Public buildings
• Technical Committee: ISO/TC 37/SC 5 - Translation, interpreting and related technology
• Drafting Committee: ISO/TC 37/SC 5 - Translation, interpreting and related technology
• Current Stage: 5000 - FDIS registered for formal approval
• Start Date: 06-Jul-2026
• Completion Date: 16-Jul-2026

• Referred By: EN ISO 17651-3:2026 - Simultaneous interpreting - Interpreters’ working environment - Part 3: Requirements and recommendations for interpreting hubs (ISO 17651-3:2026)
• Effective Date: 22-Apr-2026
• Consolidates: prEN ISO 17651-4 - Simultaneous interpreting - Interpreters’ working environment - Part 4: Requirements and recommendations for signed language interpreting (ISO/DIS 17651-4:2025)
• Effective Date: 12-Feb-2026
• Consolidates: ISO/TS 4676:2022 - Coal — Determination of carboxyreactivity
• Effective Date: 06-Jul-2024

Overview

ISO/FDIS 17651-4 addresses the working environment for signed language interpreting in conference and communicative event settings. As part of the ISO 17651 series, this draft International Standard focuses on the logistical and technical equipment requirements needed to support signed language interpreters in a safe, usable, and accessible workspace.

The standard is especially relevant where interpreters must rely on visual access, sound input, lighting, camera framing, and clear sightlines to perform simultaneous interpreting effectively. It builds on established ISO guidance for interpreters’ working environment, interpreting equipment, simultaneous interpreting delivery platforms, and conference equipment.

This document is designed to help organizers, venue operators, technical teams, and service providers create workspaces that support accessibility, teamwork, and communication quality for signed language interpreting in both meeting halls and conference halls.

Key Topics

ISO/FDIS 17651-4 covers practical requirements and recommendations for:

• Workspace layout and placement

  • Dedicated floor spaces
  • Booths for signed language interpreting
  • Interpreting hub arrangements

• Visibility and access

  • Unobstructed views of speakers, signers, and visual aids
  • Clear visual communication between interpreters and support staff
  • Safe and quick access to booths and floor workspaces

• Technical equipment

  • Lighting that reduces glare
  • Backdrops with suitable color and dimensions
  • Video displays for live images and captions
  • Camera positioning and pre-sets
  • Incoming sound through appropriate wireless receivers

• Accessibility and support

  • Compliance with accessibility requirements
  • Induction loop provision
  • Support services and technical control close to the workspace
  • Preparation materials provided in advance

The standard also highlights the importance of minimizing cognitive load and supporting the visual-manual nature of signed language communication.

Applications

This standard is intended for real-world use in:

• Conference interpreting
• Meeting halls and conference halls
• Broadcast or webcast environments
• Interpretation from dedicated booths or floor workspaces
• Hybrid and multi-language events
• Accessible event planning and venue design

It is particularly useful for events involving signed language users, deaf participants, interpreters, and technical teams who need a consistent framework for efficient service delivery.

Related Standards

ISO/FDIS 17651-4 is developed alongside and in reference to several related standards, including:

• ISO 17651-1 - Permanent booths
• ISO 17651-2 - Mobile booths
• ISO 17651-3 - Interpreting hubs
• ISO 20109 - Simultaneous interpreting equipment requirements
• ISO 24019 - Simultaneous interpreting delivery platforms
• ISO 22259 - Conference equipment
• ISO 17069 - Accessible meeting design
• ISO 21542 - Accessibility and usability of the built environment

Together, these standards support accessible, reliable, and professional signed language interpreting environments for international and conference use.

FINAL DRAFT
International
Standard
ISO/TC 37/SC 5
Simultaneous interpreting —
Secretariat: DIN
Interpreters’ working
Voting begins on:
environment —
2026-10-05
Part 4:
Voting terminates on:
2026-11-30
Requirements and
recommendations for signed
language interpreting
Interprétation simultanée — Environnement de travail des
interprètes —
Partie 4: Exigences et recommandations pour l’interprétation en
langue des signes
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/CEN PARALLEL PROCESSING LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
International
Standard
ISO/TC 37/SC 5
Simultaneous interpreting —
Secretariat: DIN
Interpreters’ working
Voting begins on:
environment —
Part 4:
Voting terminates on:
Requirements and
recommendations for signed
language interpreting
Interprétation simultanée — Environnement de travail des
interprètes —
Partie 4: Exigences et recommandations pour l’interprétation en
langue des signes
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2026
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/CEN PARALLEL PROCESSING
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
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TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
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ii
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 General requirements . 3
4.1 Workspaces.3
4.2 Siting and visibility .4
4.3 Accessibility .4
4.4 Technical control and technical support staff .4
4.5 Support services . .5
5 Equipment for workspaces — General . 5
5.1 Lighting .5
5.2 Backdrop .5
5.3 Video display .5
5.4 Camera and pre-sets .6
5.5 Incoming sound .7
5.6 Whiteboard . .7
6 On the floor . 7
6.1 Allocation of workspaces .7
6.2 Meeting hall .7
6.2.1 Interpreters’ view .7
6.2.2 Placement .7
6.2.3 Equipment .7
6.3 Conference hall .8
6.3.1 Interpreters’ view .8
6.3.2 Placement .8
6.3.3 Workspace facing the audience . 12
6.3.4 Workspace facing the rostrum . 12
6.3.5 Equipment . 12
7 Booth for signed language interpreting .13
7.1 Design — General . 13
7.2 Dimensions .14
7.3 Interpreters’ view and placement .17
7.4 Booth interior .17
7.4.1 Temperature control .17
7.4.2 Equipment .17
7.4.3 Electricity supply .18
7.4.4 Internet access .18
8 From an interpreting hub . . 19
8.1 Design — General .19
8.2 Interpreter’s view .19
9 Amenities for interpreters . 19
9.1 Toilets .19
9.2 Interpreters’ room .19
Annex A (informative) Simplified checklists .20
Annex B (informative) Flowchart .21
Annex C (informative) Workspace placements in meeting halls .22
Annex D (informative) Workspace placements in conference halls .23

iii
Annex E (informative) Layout of video displays.27
Annex F (informative) Broadcast image .32
Bibliography .35

iv
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents). ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO’s adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 37, Language and terminology, Subcommittee
SC 5, Translation, Interpreting and related technology, in collaboration with the European Committee for
Standardization, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna
Agreement).
A list of all parts in the ISO 17651 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

v
Introduction
This document concerns the logistical and technical equipment requirements and recommendations for the
working environment of signed language interpreters.
Interpreting services can be provided at a communicative event where the interpreter is at the same or
a different location as speakers, signers, participants, the audience or other interpreters. In both cases
technical support is needed. Interpreters in signed languages and spoken languages interpreting at the
same communicative event interact and collaborate with each other. As signed languages are expressed and
perceived in the visual-manual modality, interpreting into and from a signed language requires a working
environment that provides the signed language interpreter with the required audio-visual input, and an
unobstructed view of the communicative event, depending on the location of the interpreter in relation to
the speaker or signer, participant, audience and other interpreters.
Signed language interpreters interpret in various workspaces, depending on:
[1]
— the professional context such as conference interpreting (see ISO 23155 ), community interpreting
[2] [3] [4]
(see ISO 13611 ), healthcare interpreting (see ISO 21998 ) and legal interpreting (see ISO 20228 );
— the layout of the room where the communicative event takes place, such as:
— either a dedicated booth for signed language interpreting, a dedicated workspace for signed language
interpreting on the floor, or both;
— or at a distance from a booth for signed language interpreting in an interpreting hub.
This document addresses the following:
a) workspace requirements specific to signed language interpreters;
b) visual communication between interpreters and participants at an event;
c) teamwork among interpreters and among interpreters and technical support staff;
d) technical requirements and dedicated technical support;
e) dimensions and design of a dedicated booth for signed language interpreting;
f) a working environment that minimizes factors contributing to cognitive load, recognizing that
interpreting demands sustained high levels of concentration.
This document complements the existing parts 1 to 3 of the ISO 17651 series; these set out the essential
requirements for simultaneous interpreting: Part 1: Requirements and recommendations for permanent booths,
Part 2: Requirements and recommendations for mobile booths, Part 3: Requirements and recommendations for
interpreting hubs and this fourth part details comprehensively the relevant requirements for the workspaces
of signed language interpreters.
[5]
ISO/IEC Guide 71 has been used to develop an accessible standard in consultation with key stakeholders.

vi
FINAL DRAFT International Standard ISO/FDIS 17651-4:2026(en)
Simultaneous interpreting — Interpreters’ working
environment —
Part 4:
Requirements and recommendations for signed language
interpreting
1 Scope
This document specifies the logistical and technical equipment requirements and recommendations for
the working environment of signed language interpreters. This document also ensures the usability and
accessibility of workspaces of signed language interpreters.
It draws from, and adds to, the existing standards on interpreters’ working environment, interpreting
[6]
equipment, simultaneous interpreting delivery platforms and conference equipment: ISO 17651-1 ,
[7] [8] [9] [10] [11]
ISO 17651-2 , ISO 17651-3 , ISO 20109 , ISO 24019 and ISO 22259 .
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 9241-20, Ergonomics of human-system interaction — Part 20: An ergonomic approach to accessibility within
the ISO 9241 series
ISO 9241-303, Ergonomics of human-system interaction — Part 303: Requirements for electronic visual displays
ISO 17069, Accessible design — Consideration and assistive products for accessible meeting
ISO 17651-1, Simultaneous interpreting — Interpreters’ working environment — Part 1: Requirements and
recommendations for permanent booths
ISO 17651-1:2024, Simultaneous interpreting — Interpreters’ working environment — Part 1: Requirements
and recommendations for permanent booths
ISO 17651-3, Simultaneous interpreting — Interpreters’ working environment — Part 3: Requirements and
recommendations for interpreting hubs
ISO 20109:2025, Simultaneous interpreting — Equipment — Requirements
ISO 20109, Simultaneous interpreting — Equipment — Requirements
ISO 21542, Building construction — Accessibility and usability of the built environment
ISO 24019, Simultaneous interpreting delivery platforms — Requirements and recommendations
IEC 60118-4, Electroacoustics - Hearing aids - Part 4: Induction-loop systems for hearing aid purposes - System
performance requirements
IEC 60268-4, Sound system equipment - Part 4: Microphones

IEC 62489-1, Electroacoustics - Audio-frequency induction loop systems for assisted hearing - Part 1: Methods of
measuring and specifying the performance of system components
EN 1335-1, Office furniture - Office work chair - Part 1: Dimensions - Determination of dimensions
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
interpreter
person who interprets
[12]
[SOURCE: ISO 20539:2023 , 3.1.13]
3.2
interpreting
interpretation
rendering spoken or signed information from a source language into a target language in spoken or signed
form, conveying both the meaning and language register of the source language content
[12]
[SOURCE: ISO 20539:2023 , 3.1.11]
3.3
signed language
language which uses a combination of hand shapes, orientation and movement of the hands, arms or body,
and facial expressions
[12]
[SOURCE: ISO 20539:2023 , 3.1.7]
3.4
signed language interpreting
interpreting (3.2) between two signed languages (3.3) or between a signed language and a spoken language
[12]
[SOURCE: ISO 20539:2023 , 3.4.3]
3.5
simultaneous interpreting
mode of interpreting (3.2) performed while a speaker or signer is still speaking or signing
[12]
[SOURCE: ISO 20539:2023 , 3.4.12]
3.6
booth
simultaneous interpreting booth
self-contained unit enclosing the interpreter’s (3.1) workspace
Note 1 to entry: One of the purposes of booths is to provide insulation, both from the noise transmitted from the
booth’s external environment into the booth itself and vice versa, and from noise passing from one booth to another.
[12]
[SOURCE: ISO 20539:2023 , 3.5.2.1]
3.7
video display
electronic device which represents information in a visual form
[12]
[SOURCE: ISO 20539:2023 , 3.5.2.43]

3.8
overlay
substitution of part of an image by another image
[12]
[SOURCE: ISO 20539:2023 , 3.5.2.44]
3.9
accessibility
extent to which products, systems, services, environments and facilities can be used by people from a
population with the widest range
[13]
[SOURCE: ISO 9241-112:2025 , 3.11, modified — “of user needs, characteristics and capabilities to achieve
identified goals in identified contexts of use” deleted at the end of the definition; Note 1 to entry deleted]
3.10
communicative event
encounter between two or more parties during which information is transmitted
[12]
[SOURCE: ISO 20539:2023 , 3.4.32]
4 General requirements
4.1 Workspaces
Signed language interpreters interpret in diverse settings based on the nature and configuration of each
communicative event. All workspaces shall provide adequate conditions, including:
— uninterrupted incoming sound;
— clear lighting;
— unobstructed view of the room and the visual resources;
— physical comfort.
Appropriate logistical and technical arrangements shall be made to meet the above requirements.
Workspaces for signed language interpreters can be:
— a dedicated space on the floor where the communicative event is held;
— a booth for signed language interpreting at the venue where the communicative event is held;
— a booth for signed language interpreting in an interpreting hub.
When providing signed language interpreting at a communicative event, organizers and service providers
shall ensure accessibility support in accordance with ISO 17069.
When designing new rooms or renovating existing ones, workspaces for interpreters — either a booth or
a workspace on the floor, or both — shall be integrated into the structure so that the room itself and the
workspaces constitute a well-balanced unit in terms of layout, people flow within buildings, accessibility
and usability in accordance with ISO 21542.
Workspaces for interpreters shall be located away from extraneous sources of disturbance, such as kitchens,
public corridors and passageways. The workspaces shall not be placed in front of a window or an area that
produces a bright backlight.
In order to facilitate speech intelligibility, the room should not cause reverberation or echoes exceeding the
[14]
values recommended for the type of room in accordance with AS/NZS 2107 .
[14]
NOTE AS/NZS 2107 also specifies methods of measuring the background sound level and the reverberation
time in unoccupied spaces.
Technical advisors and interpreters with expert knowledge of workspaces for interpreters and related
equipment, qualified technicians or suppliers shall be consulted for the design and operation.
4.2 Siting and visibility
Signed language interpreting involves visual interaction with signing participants. To enable visual
interaction, workspaces for interpreters in a shared physical space with signing participants shall be clearly
visible and free of visual obstructions. When signers are present and interpreting from a signed language to
a spoken language is provided, the interpreters’ workspace shall be on the floor where the communicative
event is held (see 4.1 and Figure B.1). Additionally, a second signed language interpreting team can interpret
into a signed language from a booth dedicated for signed language interpreting (see Clause 7). The
interpreter can be broadcast to either screens in the same hall and venue, or publicly, or both (see Annex B).
4.3 Accessibility
It shall be possible to quickly, easily and safely access:
— the dedicated workspaces for signed language interpreting on the floor;
— one booth from another booth;
— all booths from inside or outside the room.
A booth for signed language interpreting shall be accessible to persons with a disability, in accordance with
ISO 21542.
An individual induction loop shall be provided in the room or in the booth dedicated for signed language
interpreting, and shall conform to IEC 60118-4 and IEC 62489-1.
Live captions provide access to the spoken language in text format and should be provided when requested
by the interpreters.
4.4 Technical control and technical support staff
In settings where technical equipment for signed language interpreters is used, specifically trained technical
[15]
support staff shall assist and monitor the work system of the interpreters (see ISO 6385 ) to:
— check the set-up of the dedicated interpreters’ workspaces, including the required equipment such as
cameras, lighting, backdrop, and audio receivers (see 5.2 and 7.4);
— align the dedicated lighting on the interpreter to the light in the room (see 5.1 and 7.4.2.2);
— demarcate and block off the dedicated interpreters’ workspace on the floor (e.g. with the use of a
stanchion);
— adjust or pre-set the height, zoom and framing of the camera for each of the interpreting team members;
— demonstrate and explain to the interpreting team the use of a pre-set camera control panel, if provided
(see 7.4.2.5);
— send the input to the broadcasters to display the broadcast image of the signed language interpreter,
such as on television, webcast and app streaming.
The technical controls shall be placed close to the interpreters’ workspaces so that:
— technical support staff can access them easily;
— visual communication between the technical support staff and the interpreters is possible;
— technical support staff have a clear view of the entire room, including the rostrum, speakers, signers and
all visual aids such as projection screens and displays.

The technical control should be installed:
— on a table;
— in a rack;
— in a booth that conforms to the requirements and recommendations for a permanent booth or a mobile
[6] [7]
booth for simultaneous interpreting in accordance with ISO 17651-1 or ISO 17651-2 .
If not present in the room, a central technical control shall be available in the venue.
Interpreters shall be able to communicate directly with the technical support staff, who shall have safe,
quick and easy access to the interpreters’ workspaces and the room.
NOTE In technically complex settings it has proven to be useful to have the presence of dedicated technical
support staff for the signed language interpreting team.
4.5 Support services
Signed language interpreters are unable to hold and handle documents whilst interpreting into a signed
language. Consequently, to conduct the required preparation, the event organizers shall provide signed
language interpreters with all relevant documentation prior to the start of the event.
5 Equipment for workspaces — General
5.1 Lighting
To protect the interpreter from disability glare, indirect lighting or a lamp reflector in accordance with
ISO 9241-303 shall be used. Each lighting source projected on the interpreter shall be individually and
manually adjustable for:
— beam angle;
— light intensity.
5.2 Backdrop
The backdrop behind the signed language interpreter shall cover the vertical space from the floor up. The
horizontal space shall comfortably cover the signing space of the interpreter. The following minimum
dimensions shall apply:
— width: 2,00 m;
— height: 2,30 m.
The location where the interpreter will be positioned shall be marked on the floor. The distance between the
interpreter and the backdrop shall be at least 1 m.
The backdrop shall have a uniform colour, so that the image of the interpreter can be seen without any visual
distraction. The backdrop colour value shall be mid-range. The backdrop material shall be flat without any
unevenness, non-glaring and cause no reflections.
NOTE 1 Viewers who identify as deafblind or with a visual impairment can indicate their preferred colour backdrop.
NOTE 2 Interpreters can wear plain clothes in a colour that contrasts with their skin colour.
5.3 Video display
A video display in the direct line of sight of the interpreter shall provide the incoming images as seen by the
audience on the main screen. The video display shall be positioned at a convenient ergonomic angle, i.e. with
a gaze angle from 0° to 40° and a head-tilt angle from 0° to 25° in accordance with ISO 9241-303.

For interpreters who are working directly from captions, a second video display shall provide the live text
and shall be positioned underneath or next to the camera to avoid eye strain. The video display shall be
positioned at a convenient ergonomic angle for the interpreter to read the text without the need to tilt or
move their head.
The incoming signal of the video displays shall be displayed without distorting their original aspect ratio.
Video displays shall be flat and flicker-free. They should be anti-glare and easily cleanable. The video display
shall not obstruct visibility into and from the room in which the communicative event takes place.
Screen sizes shall be in proportion to the viewing distance to ensure the interpreter can comfortably read
any displayed text. There shall be sufficient contrast between the text and the background. Both the symbols
[16]
and the screen background should have different luminance or colour, in accordance with ISO 9241-303 .
The incoming image shall follow the requirements in accordance with ISO 20109:2025, 5.2. Video displays
shall conform to ISO 20109:2025, 7.3.
The image size and quality shall be such that the visual content is readable and the speaker’s face is clearly
visible. The image of the signer shall transmit their detailed facial expression, lip and hand movements. The
image of the signer shall be framed from one hand span above their head to just below their hips so that the
hands of the signer are never out of frame. Examples of different configurations on the video display are
provided in Annex E.
NOTE 1 Good results have been achieved with:
— dual video displays with a diagonal dimension between 140 cm (55 inches) and 165 cm (65 inches) at a viewing
distance between 170 cm and 200 cm;
— single video displays with a diagonal dimension between 165 cm (65 inches) and 216 cm (85 inches) with multi-
view of the different video signals at a viewing distance between 170 cm and 200 cm.
NOTE 2 It is good practice that technical support staff and interpreters coordinate the configuration of the content
to be displayed to interpreters.
5.4 Camera and pre-sets
The camera shall be positioned at the eye level of the interpreter at a convenient ergonomic angle, i.e. with a
gaze angle from 0° to 40° and a head-tilt angle from 0° to 25° in accordance with ISO 9241-303.
The camera height shall be adjustable via a control panel automatically adapting the pre-set height of the
camera to the height of the interpreter.
The broadcast image of the interpreter shall:
— position the interpreter within the frame with sufficient space on either side to fully capture arm
movements;
— transmit the interpreter’s detailed facial expression, lip movements and hand movements;
— be framed at least 15 cm above the interpreter’s head to just below their hips so that the interpreter’s
hands are never out of frame;
— cover at least 1/3 of the horizontal plane of the display on the main screen in the room;
— not be overlayed by any other images or text.
Examples of broadcast images are provided in Annex F.
The camera shall have a frame rate of 30 (FPS) or higher to capture the fluid movements in signed language
communication, including facial expressions and mouth movements. For viewers, adequate bitrate at lower
[17][18]
resolution improves signed language comprehension over insufficient bitrate at a higher resolution.

In case of bandwidth constraints, encoders shall prioritize bitrate and compression quality over spatial
resolution.
NOTE Good results have been achieved with the following minimum bitrates for various resolutions:
— 3840×2160 (4K): 16 Mbps;
— 1920×1080 (Full HD): 8 Mbps;
— 1280×720 (HD): 4 Mbps.
5.5 Incoming sound
Incoming sound shall be provided through a wireless receiver in accordance with ISO 20109:2025, 10.3, and
shall be connected to the interpreters’ headphones, allowing for uninterrupted sound input.
NOTE Good results have been achieved with radio frequency (RF) receivers. Infrared (IR) receivers are not
suitable as the interpreters’ signing movements disrupt the IR signal.
The receiver shall allow the interpreters to select either the audio from the floor or a minimum of three pre-
set interpreted languages.
The interpreters’ headphones shall conform to ISO 20109:2025, 8.3.1.
5.6 Whiteboard
A whiteboard of A4 size with markers and wiper shall be provided for the interpreters to write information
on.
6 On the floor
6.1 Allocation of workspaces
The allocation of the interpreters’ workspace depends on the layout of the meeting hall or conference hall
[11]
and the seating arrangement of the various parties in the communicative event (see ISO 22259 ).
NOTE It is good practice that event organizers consult with the signing participants and interpreters on the
location of the interpreters’ workspace and the participants’ seating arrangements.
6.2 Meeting hall
6.2.1 Interpreters’ view
The interpreters’ workspace(s) shall be placed in such a way that the interpreters have a direct view of the
entire room, the speakers, signers and all visual resources, such as projection screens and displays.
6.2.2 Placement
In a meeting hall where all parties are physically present there are various possible workspaces. Examples
of workspaces in meeting halls are provided in Figure C.1 and Figure C.2. The workspace shall be allocated
across from the signing participants at a maximum distance of 3 m.
6.2.3 Equipment
In cases where the workspace does not provide the visibility, lighting or sound levels for interpreters to
interpret, the following shall be provided:
— lighting in accordance with 5.1;
— incoming sound in accordance with 6.3.5.5;

— a microphone in accordance with 6.3.5.7;
— video displays in accordance with 5.3.
In a small meeting hall where all participants are seated, the interpreters shall also be seated on comfortable
chairs in accordance with EN 1335-1 with the following characteristics:
— easily movable;
— adjustable height;
— adjustable or removable armrests.
A simplified checklist for an onsite communicative event without broadcast is provided in Clause A.1.
6.3 Conference hall
6.3.1 Interpreters’ view
The interpreters’ workspaces shall be placed in such a way that the interpreters have a direct unobstructed
view of the entire room, including the rostrum, speakers, signers and all visual aids, such as projection
screen and displays (see Annex D). Visual cooperation between the interpreters in the interpreting team(s)
is essential. The interpreters’ workspaces shall be situated in such a way that the interpreters’ view is
without any visual obstruction.
The logistical and technical setup shall enable all interpreters in signed languages and spoken languages
at the same communicative event to collaborate with each other from their respective workspaces. The
workspaces for signed language interpreters shall not hinder the view from the booths into the room. In
large rooms, video displays shall be used to facilitate the interpreters’ view of speakers and signers, in
accordance with ISO 20109:2025.
6.3.2 Placement
In a hall with a theatre-style seating arrangement, there are two dedicated workspaces for signed language
interpreters:
— on the floor, next to the rostrum, facing the audience (see 6.3.3);
— on the floor, facing the rostrum (see 6.3.4).
A designated area next to the rostrum facing the audience shall be allocated for signed language interpreters,
within view of all participants in the audience and without any visual obstructions (see Figure 1).
A second space at the front of the room, facing the rostrum, shall be allocated for the team of interpreters
interpreting between a signed language and a spoken language or between two signed languages (see
Figure 2).
In a communicative event, both workspaces can be used at the same time to provide interpreting: the
workspace on the conference hall floor next to the rostrum facing the audience for signing participants
and the workspace on the conference floor facing the rostrum for signers on the rostrum. When signing
participants are physically present, the workspace facing the rostrum shall be used for interpreting for
signers on the rostrum (see Figure 2).
Additionally, in cases where the conference hall has a dedicated booth for signed language interpreting (see
Clause 7), a second team can interpret into a signed language from the booth for the image to be broadcast
(see Annex F).
For each additional signed language, additional dedicated workspaces shall be provided next to the rostrum
(see Figure 3) and opposite of the rostrum (see Figure 4). If available, additional booths dedicated for signed
language interpreting can also be used for each additional signed language (see Clause 7).

Additional examples of placement of workspaces in a conference hall are provided in Figure D.1, Figure D.2,
Figure D.3 and Figure D.4.
A simplified checklist for an onsite communicative event with broadcast is provided in Clause A.2.
Figure 1 — Dedicated workspaces for interpreters on the floor of a conference hall next to the
rostrum (from a spoken language to one signed language), with a speaker at the rostrum

Figure 2 — Dedicated workspaces for interpreters on the floor of a conference hall next to the
rostrum (from a spoken to a signed language) and facing the rostrum (from a signed to a spoken
language), with a signer at the rostrum

Figure 3 — Dedicated workspaces for interpreters on the floor of a conference hall next to the
rostrum (from spoken language(s) into two signed languages), with a speaker at the rostrum
Figure 4 — Dedicated workspaces for interpreters on the floor of a conference hall next to the
rostrum (from spoken language(s) into two signed languages) and facing the rostrum (from a
signed to a spoken language), with a signer at the rostrum

6.3.3 Workspace facing the audience
The workspace facing the audience is the main workspace and shall be positioned next to the rostrum to allow
for a view of the rostrum and the signers and speakers, as well as visual contact between the interpreters
and physically present signing participants (see Figure 3). The allocated workspace shall be at least 2 m × 2
m and clearly demarcated and designed to prevent any non-interpreter from physically entering the space
(e.g. with the use of stanchions). A video display (see 5.3) shall be used to provide the interpreter facing the
audience with a view of the speaker or signer, as well as other visual materials displayed on the main screen
for the audience.
6.3.4 Workspace facing the rostrum
A second workspace for signed language interpreting shall be positioned across from the audience-facing
interpreter to allow for visual contact and cooperation between the interpreters (see Figure 2 and Figure 4).
This workspace can also be used for interpreting to signers on the rostrum. The allocated workspace shall
be clearly marked to avoid any non-interpreter physically entering the workspace.
6.3.5 Equipment
6.3.5.1 General
Workspaces shall have:
— lighting in accordance with 5.1 and 6.3.5.2;
— a backdrop in accordance with 5.2 and 6.3.5.3;
— video display(s) in accordance with 5.3 and 6.3.5.4;
— a camera in accordance with 5.4 and 6.3.5.6;
— incoming sound in accordance with 5.5 and 6.3.5.5;
— a microphone in accordance with 6.3.5.7.
6.3.5.2 Lighting
Lighting shall be provided in accordance with 5.1.
Additional lighting sources shall be used to ensure a clear image of the interpreter without shadows on the
interpreter’s body,
...

ISO/DISFDIS 17651-4
ISO/TC 37/SC 5
Secretariat: DIN
Date: 2026-07-0609-18
Simultaneous interpreting — Interpreters’ working environment —
Part 4:
Requirements and recommendations for signed language
interpreting
Interprétation simultanée — Environnement de travail des interprètes —
Partie 4: Exigences et recommandations pour l’interprétation en langue des signes
DISFDIS stage
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All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO’s member body in the country of the requester.
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ii
Contents
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 General requirements . 3
4.1 Workspaces . 3
4.2 Siting and visibility . 4
4.3 Accessibility . 4
4.4 Technical control and technical support staff . 4
4.5 Support services . 5
5 Equipment for workspaces — General . 5
5.1 Lighting . 5
5.2 Backdrop . 6
5.3 Video display . 6
5.4 Camera and pre-sets . 7
5.5 Incoming sound . 7
5.6 Whiteboard . 8
6 On the floor . 8
6.1 Allocation of workspaces . 8
6.2 Meeting hall. 8
6.3 Conference hall . 9
7 Booth for signed language interpreting . 14
7.1 Design — General . 14
7.2 Dimensions. 15
7.3 Interpreters’ view and placement . 18
7.4 Booth interior . 18
8 From an interpreting hub . 20
8.1 Design — General . 20
8.2 Interpreter’s view . 20
9 Amenities for interpreters . 21
9.1 Toilets . 21
9.2 Interpreters’ room. 21
Annex A (informative) Simplified checklists . 22
Annex B (informative) Flowchart . 23
Annex C (informative) Workspace placements in meeting halls . 24
Annex D (informative) Workspace placements in conference halls . 25
Annex E (informative) Layout of video displays . 29
Annex F (informative) Broadcast image . 34
Bibliography . 37

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents). ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO’s adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 37, Language and terminology, Subcommittee
SC 5, Translation, Interpreting and related technology, in collaboration with the European Committee for
Standardization, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna
Agreement).
A list of all parts in the ISO 17651 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
This document concerns the logistical and technical equipment requirements and recommendations for the
working environment of signed language interpreters.
Interpreting services can be provided at a communicative event where the interpreter is at the same or a
different location as speakers, signers, participants, the audience or other interpreters. In both cases technical
support is needed. Interpreters in signed languages and spoken languages interpreting at the same
communicative event interact and collaborate with each other. As signed languages are expressed and
perceived in the visual-manual modality, interpreting into and from a signed language requires a working
environment that provides the signed language interpreter with the required audio-visual input, and an
unobstructed view of the communicative event, depending on the location of the interpreter in relation to the
speaker or signer, participant, audience and other interpreters.
Signed language interpreters interpret in various workspaces, depending on:
[1]
— the professional context such as conference interpreting (see ISO 23155 ), community interpreting (see
[2] [3] [4]
ISO 13611 ), healthcare interpreting (see ISO 21998 ),) and legal interpreting (see ISO 20228 );
— the layout of the room where the communicative event takes place, such as:
— either a dedicated booth for signed language interpreting, a dedicated workspace for signed language
interpreting on the floor, or both;
— or at a distance from a booth for signed language interpreting in an interpreting hub.
This document addresses the following:
a) workspace requirements specific to signed language interpreters;
b) visual communication between interpreters and participants at an event;
c) teamwork among interpreters and among interpreters and technical support staff;
d) technical requirements and dedicated technical support;
e) dimensions and design of a dedicated booth for signed language interpreting;
f) a working environment that minimizes factors contributing to cognitive load, recognizing that
interpreting demands sustained high levels of concentration.
This document complements the existing parts 1 to 3 of the ISO 17651 series; these set out the essential
requirements for simultaneous interpreting: Part 1: Requirements and recommendations for permanent booths,
Part 2: Requirements and recommendations for mobile booths, Part 3: Requirements and recommendations for
interpreting hubs and this fourth part details comprehensively the relevant requirements for the workspaces
of signed language interpreters.
[5]
ISO/IEC Guide 71 The has been used to develop an accessible standard in consultation with key
stakeholders.
v
Simultaneous interpreting — Interpreters’ working environment —
Part 4:
Requirements and recommendations for signed language interpreting
1 Scope
This document specifies the logistical and technical equipment requirements and recommendations for the
working environment of signed language interpreters. This document also ensures the usability and
accessibility of workspaces of signed language interpreters.
It draws from, and adds to, the existing standards on interpreters’ working environment, interpreting
[23]
equipment, simultaneous interpreting delivery platforms and conference equipment: ISO 17651-1 , ISO
[7] [8] [9] [10] [19]
17651-2 , ISO 17651-3 , ISO 20109 , ISO 24019 and ISO 22259 .
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 9241-20, Ergonomics of human-system interaction — Part 20: An ergonomic approach to accessibility within
the ISO 9241 series
ISO 9241-303, Ergonomics of human-system interaction — Part 303: Requirements for electronic visual displays
ISO 17069, Accessible design — Consideration and assistive products for accessible meeting
ISO 17651-1, Simultaneous interpreting — Interpreters’ working environment — Part 1: Requirements and
recommendations for permanent booths
ISO 17651-1:2024, Simultaneous interpreting — Interpreters’ working environment — Part 1: Requirements
and recommendations for permanent booths
ISO 17651-3, Simultaneous interpreting — Interpreters’ working environment — Part 3: Requirements and
recommendations for interpreting hubs
ISO 20109:2025, Simultaneous interpreting — Equipment — Requirements
ISO 20109, Simultaneous interpreting — Equipment — Requirements
ISO 21542, Building construction — Accessibility and usability of the built environment
ISO 24019, Simultaneous interpreting delivery platforms — Requirements and recommendations
IEC 60118-4, Electroacoustics - Hearing aids - Part 4: Induction-loop systems for hearing aid purposes - System
performance requirements
IEC 60268-4, Sound system equipment - Part 4: Microphones
IEC 62489-1, Electroacoustics - Audio-frequency induction loop systems for assisted hearing - Part 1: Methods of
measuring and specifying the performance of system components
EN 1335-1, Office furniture - Office work chair - Part 1: Dimensions - Determination of dimensions
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at httphttps://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1
interpreter
person who interprets
[12]
[SOURCE: ISO 20539:2023 , 3.1.13]
3.2
interpreting
interpretation
rendering spoken or signed information from a source language into a target language in spoken or signed
form, conveying both the meaning and language register of the source language content
[12]
[SOURCE: ISO 20539:2023 , 3.1.11]
3.3
signed language
language which uses a combination of hand shapes, orientation and movement of the hands, arms or body,
and facial expressions
[12]
[SOURCE: ISO 20539:2023 , 3.1.7]
3.4
signed language interpreting
interpreting (3.2) between two signed languages (3.3) or between a signed language and a spoken language
[12]
[SOURCE: ISO 20539:2023 , 3.4.3]
3.5
simultaneous interpreting
mode of interpreting (3.2) performed while a speaker or signer is still speaking or signing
[12]
[SOURCE: ISO 20539:2023 , 3.4.12]
3.6
booth
simultaneous interpreting booth
self-contained unit enclosing the interpreter’s (3.1) workspace
Note 1 to entry: One of the purposes of booths is to provide insulation, both from the noise transmitted from the booth’s
external environment into the booth itself and vice versa, and from noise passing from one booth to another.
[12]
[SOURCE: ISO 20539:2023 , 3.5.2.1]
3.7
video display
electronic device which represents information in a visual form
[12]
[SOURCE: ISO 20539:2023 , 3.5.2.43]
3.8
overlay
substitution of part of an image by another image
[12]
[SOURCE: ISO 20539:2023 , 3.5.2.44]
3.9
accessibility
extent to which products, systems, services, environments and facilities can be used by people from a
population with the widest range
[13]
[SOURCE: ISO 9241-112:2025 , 3.11, modified - "— “of user needs, characteristics and capabilities to
achieve identified goals in identified contexts of use” deleted at the end of the definition; Note 1 to entry
deleted]
3.10
communicative event
encounter between two or more parties during which information is transmitted
[12]
, 3.4.32]
[SOURCE: ISO 20539:2023
4 General requirements
4.1 Workspaces
Signed language interpreters interpret in diverse settings based on the nature and configuration of each
communicative event. All workspaces shall provide adequate conditions, including:
— uninterrupted incoming sound;
— clear lighting;
— unobstructed view of the room and the visual resources;
— physical comfort.
Appropriate logistical and technical arrangements shall be made to meet the above requirements.
Workspaces for signed language interpreters can be:
— a dedicated space on the floor where the communicative event is held;
— a booth for signed language interpreting at the venue where the communicative event is held;
— a booth for signed language interpreting in an interpreting hub.
When providing signed language interpreting at a communicative event, organizers and service providers
shall ensure accessibility support in accordance with ISO 17069.
When designing new rooms or renovating existing ones, workspaces for interpreters — either a booth, or a
workspace on the floor, or both — shall be integrated into the structure so that the room itself and the
workspaces constitute a well-balanced unit in terms of layout, people flow within buildings, accessibility and
usability in accordance with ISO 21542.
Workspaces for interpreters shall be located away from extraneous sources of disturbance, such as kitchens,
public corridors and passageways. The workspaces shall not be placed in front of a window or an area that
produces a bright backlight.
In order to facilitate speech intelligibility, the room should not cause reverberation or echoes exceeding the
[14]
values recommended for the type of room in accordance with AS/NZS 2107 .
[14]
NOTE AS/NZS 2107 also specifies methods of measuring the background sound level and the reverberation time
in unoccupied spaces.
Technical advisors and interpreters with expert knowledge of workspaces for interpreters and related
equipment, qualified technicians or suppliers shall be consulted for the design and operation.
4.2 Siting and visibility
Signed language interpreting involves visual interaction with signing participants. To enable visual
interaction, workspaces for interpreters in a shared physical space with signing participants shall be clearly
visible and free of visual obstructions. When signers are present and interpreting from a signed language to a
spoken language is provided, the interpreters’ workspace shall be on the floor where the communicative event
is held (see 4.1 and Figure B.1). Additionally, a second signed language interpreting team can interpret into a
signed language from a booth dedicated for signed language interpreting (see Clause 7). The interpreter can
be broadcast to either screens in the same hall and venue, or publicly, or both (see Annex B).
4.3 Accessibility
It shall be possible to quickly, easily and safely access:
— the dedicated workspaces for signed language interpreting on the floor;
— one booth from another booth;
— all booths from inside or outside the room.
A booth for signed language interpreting shall be accessible to persons with a disability, in accordance with
ISO 21542.
An individual induction loop shall be provided in the room or in the booth dedicated for signed language
interpreting, and shall conform to IEC 60118-4 and IEC 62489-1.
Live captions provide access to the spoken language in text format and should be provided when requested
by the interpreters.
4.4 Technical control and technical support staff
In settings where technical equipment for signed language interpreters is used, specifically trained technical
[15]
support staff shall assist and monitor the work system of the interpreters (see ISO 6385 ) to:
— check the set-up of the dedicated interpreters’ workspaces, including the required equipment such as
cameras, lighting, backdrop, and audio receivers (see 5.2 and 7.4);
— align the dedicated lighting on the interpreter to the light in the room (see 5.1 and 7.4.2.2);
— demarcate and block off the dedicated interpreters’ workspace on the floor, for example (e.g. with the use
of a stanchion;);
— adjust or pre-set the height, zoom and framing of the camera for each of the interpreting team members;
— demonstrate and explain to the interpreting team the use of a pre-set camera control panel, if provided
(see 7.4.2.5);
— send the input to the broadcasters to display the broadcast image of the signed language interpreter, such
as on television, webcast and app streaming.
The technical controls shall be placed close to the interpreters’ workspaces so that:
— technical support staff can access them easily;
— visual communication between the technical support staff and the interpreters is possible;
— technical support staff have a clear view of the entire room, including the rostrum, speakers, signers and
all visual aids such as projection screens and displays.
The technical control should be installed:
— on a table;
— in a rack;
— in a booth that conforms to the requirements and recommendations for a permanent booth or a mobile
[23] [7]
booth for simultaneous interpreting in accordance with ISO 17651-1 or ISO 17651-2 .
If not present in the room, a central technical control shall be available in the venue.
Interpreters shall be able to communicate directly with the technical support staff, who shall have safe, quick
and easy access to the interpreters’ workspaces and the room.
NOTE In technically complex settings it has proven to be useful to have the presence of dedicated technical support
staff for the signed language interpreting team.
4.5 Support services
Signed language interpreters are unable to hold and handle documents whilst interpreting into a signed
language. Consequently, to conduct the required preparation, the event organizers shall provide signed
language interpreters with all relevant documentation prior to the start of the event.
5 Equipment for workspaces: general — General
5.1 Lighting
To protect the interpreter from disability glare, indirect lighting or a lamp reflector in accordance with ISO
9241-303 shall be used. Each lighting source projected on the interpreter shall be individually and manually
adjustable for:
— beam angle;
— light intensity.
5.2 Backdrop
The backdrop behind the signed language interpreter shall cover the vertical space from the floor up. The
horizontal space shall comfortably cover the signing space of the interpreter. The following minimum
dimensions shall apply:
— width: 2,00 m;
— height: 2,30 m.
The location where the interpreter will be positioned shall be marked on the floor. The distance between the
interpreter and the backdrop shall be at least 1 m.
The backdrop shall have a uniform colour, so that the image of the interpreter can be seen without any visual
distraction. The backdrop colour value shall be mid-range. The backdrop material shall be flat without any
unevenness, non-glaring and cause no reflections.
NOTE 1 Viewers who identify as deafblind or with a visual impairment can indicate their preferred colour backdrop.
NOTE 2 Interpreters can wear plain clothes in a colour that contrasts with their skin colour.
5.3 Video display
A video display in the direct line of sight of the interpreter shall provide the incoming images as seen by the
audience on the main screen. The video display shall be positioned at a convenient ergonomic angle, i.e. with
a gaze angle from 0° to 40° and a head-tilt angle from 0° to 25° in accordance with ISO 9241-303.
For interpreters who are working directly from captions, a second video display shall provide the live text and
shall be positioned underneath or next to the camera to avoid eye strain. The video display shall be positioned
at a convenient ergonomic angle for the interpreter to read the text without the need to tilt or move their head.
The incoming signal of the video displays shall be displayed without distorting their original aspect ratio.
Video displays shall be flat and flicker-free. They should be anti-glare and easily cleanable. The video display
shall not obstruct visibility into and from the room in which the communicative event takes place.
Screen sizes shall be in proportion to the viewing distance to ensure the interpreter can comfortably read any
displayed text. There shall be sufficient contrast between the text and the background. Both the symbols and
[16]
the screen background should have different luminance or colour, in accordance with ISO 9241-303 .
The incoming image shall follow the requirements in accordance with ISO 20109:2025, 5.2. Video displays
shall conform to ISO 20109:2025, 7.3.
The image size and quality shall be such that the visual content is readable and the speaker’s face is clearly
visible. The image of the signer shall transmit their detailed facial expression, lip and hand movements. The
image of the signer shall be framed from one hand span above their head to just below their hips so that the
hands of the signer are never out of frame. Examples of different configurations on the video display are
provided in Annex E.
NOTE 1 Good results have been achieved with:
— dual video displays with a diagonal dimension between 140 cm (55 inches) and 165 cm (65 inches) at a viewing
distance between 170 cm and 200 cm;
— single video displays with a diagonal dimension between 165 cm (65 inches) and 216 cm (85 inches) with multi-
view of the different video signals at a viewing distance between 170 cm and 200 cm.
NOTE 2 It is good practice that technical support staff and interpreters coordinate the configuration of the content to
be displayed to interpreters.
5.4 Camera and pre-sets
The camera shall be positioned at the eye level of the interpreter at a convenient ergonomic angle, i.e. with a
gaze angle from 0° to 40° and a head-tilt angle from 0° to 25° in accordance with ISO 9241-303.
The camera height shall be adjustable via a control panel automatically adapting the pre-set height of the
camera to the height of the interpreter.
The broadcast image of the interpreter shall:
— position the interpreter within the frame with sufficient space on either side to fully capture arm
movements;
— transmit the interpreter’s detailed facial expression, lip movements and hand movements;
— be framed at least 15 cm above the interpreter’s head to just below their hips so that the interpreter’s
hands are never out of frame;
— cover at least 1/3 of the horizontal plane of the display on the main screen in the room;
— not be overlayed by any other images or text.
Examples of broadcast images are provided in Annex F.
The camera shall have a frame rate of 30 (FPS) or higher to capture the fluid movements in signed language
communication, including facial expressions and mouth movements. For viewers, adequate bitrate at lower
[17] [18]
resolution improves signed language comprehension over insufficient bitrate at a higher resolution. In
case of bandwidth constraints, encoders shall prioritize bitrate and compression quality over spatial
resolution.
NOTE Good results have been achieved with the following minimum bitrates for various resolutions:
— 3840×2160 (4K): 16 Mbps;
— 1920×1080 (Full HD): 8 Mbps;
— 1280×720 (HD): 4 Mbps.
5.5 Incoming sound
Incoming sound shall be provided through a wireless receiver in accordance with ISO 20109:2025, 10.3, and
shall be connected to the interpreters’ headphones, allowing for uninterrupted sound input.
NOTE Good results have been achieved with radio frequency (RF) receivers. Infrared (IR) receivers are not suitable
as the interpreters’ signing movements disrupt the infraredIR signal.
The receiver shall allow the interpreters to select either the audio from the floor or a minimum of three pre-
set interpreted languages.
The interpreters’ headphones shall conform to ISO 20109:2025, 8.3.1.
5.6 Whiteboard
A whiteboard of A4 size with markers and wiper shall be provided for the interpreters to write information
on.
6 On the floor
6.1 Alloc
...