ISO/IEC 15411:1999

INTERNATIONAL ISO/IEC
STANDARD 15411
First edition
1999-10-15
Information technology — Segmented
keyboard layouts
Technologies de l'information — Disposition des claviers segmentés
Reference number
©
ISO/IEC 1999
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ii © ISO/IEC 1999 – All rights reserved

Contents Page
1 Scope .1
2 Normative references .1
3 Definitions .1
4 Guiding principles .4
5 Design requirements and measurement metrics .5
6 Requirements for adjustable segmented keyboards.6
7 Fixed angle segmented keyboards.7
8 Conformance.8
Annex A (informative) Segmented keyboard layouts.10
Bibliography .13
© ISO/IEC 1999 – All rights reserved iii

Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission)
form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC
participate in the development of International Standards through technical committees established by the
respective organization to deal with particular fields of technical activity. ISO and IEC technical committees
collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental, in
liaison with ISO and IEC, also take part in the work.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
In the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
Draft International Standards adopted by the joint technical committee are circulated to national bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
International Standard ISO/IEC 15411 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information
technology, Subcommittee SC 35, User interfaces.
Annex A of this International Standard is for information only.
iv © ISO/IEC 1999 – All rights reserved

Introduction
This International Standard provides guidance on the technical requirements which are important in the three-
dimensional layout of segmented keyboards.
Segmentation of the alphanumeric section of the keyboard allows the two segments to be placed in non-coplanar
and non-linear alignment. Segmented keyboards are intended to allow altered spatial layout of the keyboard
segments relative to the user. The altered orientation may allow the user to attain greater comfort, to decrease the
rate of onset of fatigue and to reduce the possibility of pain.
Major contributing influences on the effectiveness and productivity provided by a segmented keyboard are the
typing skills of the user. Touch typists can take full advantage of the differing angles provided, whereas, unskilled
users may find some alternative keyboard layouts unusable.
It should be noted that, for a significant portion of the population, the standard keyboard may provide the correct
spatial configuration. Enforcing unwanted keyboard angles upon these individuals could have negative effects.
© ISO/IEC 1999 – All rights reserved v

INTERNATIONAL STANDARD ISO/IEC 15411:1999(E)
Information technology — Segmented keyboard layouts
1 Scope
This International Standard defines the differing requirements necessary when considering the various types of
segmented keyboards. The scope of this International Standard encompasses the three-dimensional layout of
segmented, traditional style keyboards classified as having:
a. Adjustable alphanumeric segments;
b. Fixed angle alphanumeric segments.
This International Standard covers the following keyboard areas:
- Alphanumeric area
- Function area
- Text editing area
- Numeric area
- Cursor control area
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 7000:1989, Graphical symbols for use on equipment — Index and synopsis.
ISO 9241-4:1998, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 4: Keyboard
requirements.
ISO 9241-9, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 9: Requirements for non-
keyboard input devices.
ISO/IEC 9995-1:1994, Information technology —- Keyboard layouts for text and office systems — Part 1: General principles
governing keyboard layouts.
ISO/IEC 9995-2:1994, Information technology — Keyboard layouts for text and office systems — Part 2: Alphanumeric section.
ISO/IEC 9995-3:1994, Information technology — Keyboard layouts for text and office systems — Part 3: Complementary layouts
of the alphanumeric zone of the alphanumeric section.
ISO/IEC 9995-4:1994, Information technology — Keyboard layouts for text and office systems — Part 4: Numeric section.
ISO/IEC 9995-5:1994, Information technology — Keyboard layouts for text and office systems — Part 6: Editing section.
ISO/IEC 9995-6:1994, Information technology — Keyboard layouts for text and office systems — Part 6: Function section.
3 Definitions
For the purposes of this International Standard, the following definitions apply.
© ISO/IEC 1999 – All rights reserved 1

3.1
adjustable segmented keyboard
a keyboard which has the alphanumeric section divided into two segments which can be moved relative to each
other in any plane
3.2
alphanumeric keyboard
a matrix of keys as specified in ISO/IEC 9995-1
3.3
alphanumeric section
as defined in ISO/IEC 9995-2
3.4
cursor control keys
as defined in ISO/IEC 9995-5
3.5
editing section
as defined in ISO/IEC 9995-5
3.6
fixed angle segmented keyboard
a keyboard which has the alphanumeric section divided into two segments which are fixed relative to each other,
not necessarily linear or co-planar
3.7
function section
as defined in ISO/IEC 9995-6
3.8
home row of keys
row C as defined in ISO/IEC 9995-1
3.9
keyboard
an arrangement of typing and function keys laid out in a specified manner
3.10
lateral inclination ����
the angle (�) formed by the inclination of the central regions of the alphanumeric segments relative to the horizontal
plane, calculated from the angle of the line formed by the tops of the undepressed keys C01 and C05 on the left
segment, and C06 and C10 (see Key position numbering system ISO/IEC 9995-1) on the right segment and the
horizontal plane (see Figure 2)
NOTE Lateral inclination is intended to alter pronation/supination angles.
3.11
neutral posture
for flexion/extension and ulnar deviation/radial deviation, neutral wrist posture is defined in ISO 9241-9
NOTE For this International Standard, neutral wrist posture also encompasses pronation and supination. This is the rotation of
the forearm where the person does not exert significant muscular effort in rotation of the forearm in either pronation or
supination.
3.12
numeric keyboard or numeric keypad
an array of three rows of three keys (for the numerals 1 - 9), a zero/decimal area and any additional optional keys
NOTE The numeric keypad may be permanently affixed, detachable or separate from the alphanumeric segments.
2 © ISO/IEC 1999 – All rights reserved

3.13
numeric section
as defined in ISO/IEC 9995-4
3.14
pronation
as defined in ISO 9241-9
3.15
radial deviation
as defined in ISO 9241
3.16
shoulder abduction
movement of the upper arm laterally away from the body
3.17
shoulder flexion
movement of the upper arm in a forward direction
3.18
slope��
��
the angle (�) formed by the elevation of the back (or front) of the keyboard, calculated from the height difference
between rows A and E (see Figure 2)
NOTE Slope adjustment can influence wrist flexion/extension.
3.19
splay angle��
��
the angle (�) formed by the two alphanumeric segments; measured as the angle formed by the perpendiculars of
the line drawn through the centres of the home row of keys: for the left segment, the centre of keys C01 and C05;
for the right segment C06 and C10 (see ISO/IEC 9995-1)
NOTE Splay adjustment is used to reduce ulnar deviation (see Figure 1).
�
Figure 1 — Splay angle���� of a segmented keyboard
© ISO/IEC 1999 – All rights reserved 3

�
�
Figure 2 — Slope�� and lateral inclination�� of a segmented keyboard
�� ��
3.20
supination
as defined in ISO 9241-9
3.21
ulnar deviation
as defined in ISO 9241-9
3.22
Visual Display Terminal (VDT)
the equipment by which users interact with a computer system
NOTE A VDT will generally present information on a display. It also provides the means for inputting information into a
computer system, most commonly by means of a keyboard. The term VDT includes both the display and the keyboard and any
other electronic equipment required to support the terminal.
3.23
wrist extension
as defined in ISO 9241-9 (also known as dorsiflexion)
3.24
wrist flexion
as defined in ISO 9241-9
3.25
wrist rest
a surface or apparatus to support the forearm at the wrist during typing or in between typing bouts
4 Guiding principles
Design of the segmented keyboard requires the consideration of the population’s and individual user’s: gender,
anthropometric dimensions, ranges of movement and positions of comfort. Both adjustable and fixed angle
segmented keyboards have the aim of improving wrist and upper limb posture by segmenting the alphanumeric
sections of the keyboard and angling them to advantageously alter their spatial relationship relative to the user.
This segmentation allows for the reduction of pronation and ulnar deviation. The altered positions are intended to
permit the attainment of neutral wrist postures without adversely altering the natural posture of the rest of the body
or the productivity of the user.
Major contributing influences on the effectiveness and productivity provided by a segmented keyboard, are the
typing skills of the user. Touch typists can take full advantage of the differing angles provided, whereas, unskilled
users may find some alternative keyboard layouts unusable. For the unskilled user, the ability to be able to easily
4 © ISO/IEC 1999 – All rights reserved

sight the keys is an essential part of typing. Acute lateral angulation (�) may make it more difficult to see the key
legends. Similarly, increasing the splay (�) angle can create a split in the visual field.
The adjustable segmented keyboard allows the user to find the appropriate angles for their individual anatomical
and work requirements. By varying the splay (�) and lateral inclination (�) of the left and right keyboard segments,
the user of the adjustable segmented keyboard should be able to adjust the keyboard to attain the greatest amount
of comfort and productivity during typing. That is, the keyboard should allow the user to obtain neutral wrist
postures by elevating the central region of the keyboard to reduce pronation; and to provide a separation of the
alphanumeric segments to reduce ulnar deviation. The user may empirically find the most suitable angle for
comfort and productivity.
The fixed, angle segmented keyboard also aims to allow neutral wrist postures by compensating for pronation and
ulnar deviation of the forearms and wrists. These keyboards, because of their intrinsic fixed designs, approximate
the required angles for the general population. Design of the keyboard will by necessity be a compromise between
the choice of angles, the population’s variances and the typing skills of the users. These variables need to be
considered by the manufacturer in their selection of segment angles.
5 Design requirements and measurement metrics
Mandatory requirements are identified by the presence of the word "shall"; "should" statements are
recommendations and usually objectively quantified.
Design requirements have three sections:
a. The general requirements for segmented keyboards within the scope of this International Standard (clause
5); and further specific requirements describing:
b. Adjustable segmented keyboards (clause 6). Both ISO/IEC 9995 conformant (subclause 6.2.1) and non
conformant (subclause 6.2.2); and also
c. Fixed angle segmented keyboards (clause 7).
5.1 General design of the keyboard
5.1.1 Segmentation of alphanumeric section
The alphanumeric section shall be divided such that columns to the left of and including column 05 (see ISO/IEC
9995-1, clause 7) shall be allocated to left hand usage and columns to the right of and including column 06
allocated for right hand usage.
5.1.2 Key position E6
Key position E6 may be allocated to either left or right hand usage.
5.1.3 Numeric key pad alignment
If there is a numeric keypad provided, its angle relative to the user should not be dependent on the adjustment of
the main section.
5.1.4 Dimensions of the keyboard
The minimum size of the keyboard is limited by the requirements for key spacing and key top size (see
ISO 9241-4). The overall dimension of the keyboard should exceed this minimum size by as little as possible.
5.1.5 Slope of the keyboard (����)
The slope of the individual key segments shall comply with ISO 9241-4.
5.1.6 Adjusting mechanism
All keyboards may be adjustable in slope, and in the case of adjustable segmented keyboards, in splay, and lateral
inclination from the horizontal.
© ISO/IEC 1999 – All rights reserved 5

Where an adjusting mechanism is provided, it shall not compromise stability, ease of use and placement.
Adjustment should not change unintentionally. Tools shall not be required for adjustment purposes.
5.2 Positioning of keys
5.2.1 Key positioning and centre line spacing
For the adjustable segmented keyboard in the closed state, the spacing between columns 05 and 06 may be
greater than the 19 mm centre to centre, the normal requirement for the adjustable keyboard in the closed state.
For the fixed angle segmented keyboard, this distance will depend on the splay angle between the alphanumeric
segments and their fixed positions relative to one another.
5.2.2 Cursor keys
Cursor control keys should be positioned as defined in ISO/IEC 9995-5. In the case of some segmented
keyboards, geometrical and space considerations may necessitate moving the cursor keys to other non-standard
positions. Although this is permissible, placement should be in the bottom right corner of zone ZA3 (see ISO/IEC
9995-1) for adjustable segmented keyboards. For fixed angle segmented keyboards, cursor keys can be placed
between the alphanumeric segments.
5.2.3 Function keys
Function keys should be positioned as defined in ISO/IEC 9995-6. In the case of some segmented keyboards,
geometrical and space considerations may necessitate moving the function keys to other non-standard positions
but these designs shall attain compliance via subclause 6.2.2 of this International Standard.
5.2.4 Numeric key pad
If provided, the ten digits, zero to nine shall be allocated to keys in section ZN0 (Layout and allocation of the
numeric section are specified in ISO/IEC 9995-6).
Segmented keyboards may have detachable numeric keypads that could be placed on either side of the
alphanumeric sections.
5.2.5 Text editing keys
Layout and allocation of the text editing section should be as specified in ISO/IEC 9995-5. Alternative positions
may be used for symmetry and space reasons.
5.2.6 Keys in row Z
One row of cursor keys may reside in row Z; and the space bar may be made deeper to occupy both row A and
row Z.
6 Requirements for adjustable segmented keyboards
6.1 Adjustment requirements
The adjustable segmented keyboard should allow the user to adjust the left and right hand alphanumeric segments
so that the greatest comfort during use may be achieved. That is, obtain neutral wrist postures by elevating the
central region of the keyboard sections to reduce pronation (angle �); and permit an opening splay angle (angle �)
at the leading edge of the segments to reduce ulnar deviation in both arms.
Some combination of these adjustments should allow neutral wrist postures. Inadvertent increases in radial
deviation, wrist flexion or extension should be avoided.
6.1.1 Slope angle
As defined in ISO 9241-4.
6.1.2 Lateral inclination angle (��)
��
The maximum adjusted lateral inclination angle (�) from the horizontal should be in the range 0� to 45�.
The keyboard should be constructed so that the left and right outer segment edges cannot be higher than the
centre region. That is, it should not increase pronation of the forearms.
6 © ISO/IEC 1999 – All rights reserved

6.1.3 Adjustment for splay (����)
The splay angle (�) between the two alphanumeric segments should be adjustable within the range 0� to 30�.
Splay should not be greater than 30�.
The keyboard should be constructed so that it cannot assume a shape that allows the front edge to have a smaller
opening than the back edge. That is, it should not increase ulnar deviation of the hands.
6.1.4 Height of adjustable segmented keyboard
The height of the key rows shall be measured from the centre of the key top of an undepressed key in each row to
the supporting work surface of the keyboard.
The adjustable segmented keyboard shall have at least one position of adjustment where the height of the
keyboard at the home row (row C) complies with ISO 9241-4.
It is recommended that for any adjusted position, the height of the C06 key should not exceed 100 mm above the
desk surface.
6.2 Adjustable keyboards: ISO/IEC 9995 conformant and non-conformant
Keyboards with segmented and adjustable alphanumeric sections are divided into two requirement subclauses:
those that conform with ISO/IEC 9995-2 in at least one position of adjustment and those that cannot conform to
ISO/IEC 9995-2 in any of their ranges of adjustment. Keyboards in both subclauses shall conform to subclauses
5.1 to 6.1.4 of this International Standard.
6.2.1 Adjustable keyboards: ISO/IEC 9995 conformant
A keyboard with adjustable alphanumeric segments shall have at least one position that allows it to conform to
ISO/IEC 9995-2, with the proviso of subclause 6.2.1.1.
6.2.1.1 Separation between columns 05 and 06
Where the segmentation between the two alphanumeric segments occurs (between columns 05 and 06), a larger
distance between two adjacent keys than that required by ISO 9241-4 subclause 6.2.1 may be used.
In the closed position, this distance should be minimized so that the keyboard does not differ significantly from a
non-segmented linear keyboard conforming to ISO/IEC 9995.
6.2.2 Adjustable keyboards: ISO/IEC 9995 non-conformant
Due to its shape or function, an adjustable, segmented keyboard may not conform to ISO/IEC 9995-2 in any of its
ranges of adjustment but will conform with this International Standard provided that the requirements of subclauses
5.1 to 6.1.4 are met, and that it complies with the test method defined in ISO 9241-4.
7 Fixed angle segmented keyboards
For conformance, keyboards with fixed angle segmented alphanumeric sections shall conform to all general
requirements of subclauses 5.1 to 5.2.6 plus subclauses 7.1 to 7.4.
7.1 Lateral inclination angle
The keyboard should be constructed so that the alphanumeric segment's outer edges are not higher than the
centre region (�W 0�). That is, the keyboard should not increase pronation of the forearms.
7.2 Splay angle
The splay angle (�) should range from 0� to 18�, and should not exceed 25�.
7.3 Wrist rests
The keyboard can be provided with optional wrist rests. If provided, wrist rests shall not impair normal typing.
7.4 Conformance and testing
To obtain conformance in this category, the keyboard shall undergo testing via ISO 9241-4.
© ISO/IEC 1999 – All rights reserved 7

8 Conformance
A segmented keyboard may attain conformance with this International Standard by meeting the requirements of
one of three conformance levels.
Level 1 Conformance for adjustable keyboards
A segmented adjustable keyboard is in conformance with this International Standard at level 1 if it meets the
requirements specified in subclauses:
5.1 to 5.2.6: General design requirements and measurement metrics;
6.1 to 6.14: Requirements for adjustable segmented keyboards and;
6.2.1 to 6.2.1.1: Adjustable keyboards: ISO/IEC 9995 compliant.
Level 2 Conformance for adjustable keyboards
An adjustable keyboard that cannot be adjusted to conform to the level 1 conformance level may attain
conformance at level 2 of this International Standard b
...