SIST EN ISO 9241-9:2002

SLOVENSKI STANDARD
01-januar-2002
Ergonomic requirements for office work with visual display terminals (VDTs) - Part
9: Requirements for non-keyboard input devices (ISO 9241-9:2000)
Ergonomic requirements for office work with visual display terminals (VDTs) - Part 9:
Requirements for non-keyboard input devices (ISO 9241-9:2000)
Ergonomische Anforderungen für Bürotätigkeiten mit Bildschirmgeräten - Teil 9:
Anforderungen an Eingabemittel-ausgenommen Tastaturen (ISO 9241-9:2000)
Exigences ergonomiques pour travail de bureau avec terminaux a écrans de
visualisation (TEV) - Partie 9: Exigences relatives aux dispositifs d'entrée autres que les
claviers (ISO 9241-9:2000)
Ta slovenski standard je istoveten z: EN ISO 9241-9:2000
ICS:
13.180 Ergonomija Ergonomics
35.180 Terminalska in druga IT Terminal and other
periferna oprema IT peripheral equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL ISO
STANDARD 9241-9
First edition
2000-02-15
Ergonomic requirements for office work
with visual display terminals (VDTs) —
Part 9:
Requirements for non-keyboard input
devices
Exigences ergonomiques pour travail de bureau avec terminaux à écrans
de visualisation (TEV) —
Partie 9: Exigences relatives aux dispositifs d'entrée autres que les claviers
Reference number
ISO 9241-9:2000(E)
©
ISO 2000
ISO 9241-9:2000(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not
be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this
file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this
area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters
were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event
that a problem relating to it is found, please inform the Central Secretariat at the address given below.
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body
in the country of the requester.
ISO copyright office
Case postale 56 � CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 734 10 79
E-mail copyright@iso.ch
Web www.iso.ch
Printed in Switzerland
ii © ISO 2000 – All rights reserved

ISO 9241-9:2000(E)
Contents Page
1 Scope .1
2 Normative references .1
3 Terms and definitions .2
3.1 Actions.2
3.2 Feedback .3
3.3 Hardware.3
3.4 Measures .7
3.5 Posture.8
3.6 Usability indicators.11
4 Guiding principles .11
4.1 General.11
4.2 Operability .11
4.3 Controllability.12
4.4 Biomechanical load .13
5 Performance criterion .13
6 Design requirements and recommendations .13
6.1 General requirements and recommendations.13
6.2 Specific input device requirements and recommendations .16
7 Measurement conditions and conventions.21
7.1 General.21
7.2 Types of measurements.21
7.3 Required measurements.22
7.4 Legibility legends’ and symbols identification of graphic symbols.22
8 Conformance.24
Annex A (informative) Input device selection, usability testing and analysis .25
Annex B (informative) Testing of efficiency and effectiveness.28
Annex C (informative) Assessment of comfort .37
Annex D (informative) Additional evaluation methods.41
Bibliography.42
ISO 9241-9:2000(E)
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this part of ISO 9241 may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 9241-9 was prepared by Technical Committee ISO/TC 159, Ergonomics, Subcommittee
SC 4, Ergonomics of human-system interaction.
ISO 9241 consists of the following parts, under the general title Ergonomic requirements for office work with visual
display terminals (VDTs):
� Part 1: General introduction
� Part 2: Guidance on task requirements
� Part 3: Visual display requirements
� Part 4: Keyboard requirements
� Part 5: Workstation layout and postural requirements
� Part 6: Guidance on the work environment
� Part 7: Requirements for display with reflections
� Part 8: Requirements for displayed colours
� Part 9: Requirements for non-keyboard input devices
� Part 10: Dialogue principles
� Part 11: Guidance on usability
� Part 12: Presentation of information
� Part 13: User guidance
� Part 14: Menu dialogues
� Part 15: Command dialogues
iv © ISO 2000 – All rights reserved

ISO 9241-9:2000(E)
� Part 16: Direct manipulation dialogues
� Part 17: Form filling dialogues
Annexes A, B, C and D of this part of ISO 9241 are for information only.
ISO 9241-9:2000(E)
Introduction
Non-keyboard input devices are commonly used by operators to perform tasks with interactive office computer
systems. Input device design can have a significant impact on efficiency, effectiveness and satisfaction. The
requirements and recommendations are based on ergonomic principles.
The design requirements and recommendations are intended to address the fifth to ninety-fifth percentile of the
population. However, when possible, non-keyboard input devices should be designed to accommodate the
anthropometric characteristics of the intended user population.
Annexes A to D are included to provide information on potential methods of testing input devices and to encourage
institutions or individuals to conduct research on these methods such that further validation can be supplied.
vi © ISO 2000 – All rights reserved

INTERNATIONAL STANDARD ISO 9241-9:2000(E)
Ergonomic requirements for office work with visual display
terminals (VDTs) —
Part 9:
Requirements for non-keyboard input devices
1 Scope
This part of ISO 9241 provides requirements and recommendations for the design of non-keyboard input devices. It
only includes devices for which there exists sufficient published ergonomic information.
This part of ISO 9241 applies to several types of non-keyboard input devices designed for stationary use. It
provides guidance based on ergonomic factors for the following input devices: mice, pucks, joysticks, trackballs,
tablets and overlays, touch-sensitive screens, styli, and light pens. It gives guidance on the design of these devices
used for typical office tasks so that the limitations and capabilities of users are considered. This part of ISO 9241
specifies methods for determining conformance through observation, performance, and by measuring the physical
attributes of the various devices.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this part of ISO 9241. For dated references, subsequent amendments to, or revisions of, any of these publications
do not apply. However, parties to agreements based on this part of ISO 9241 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 9241-3, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 3: Visual display
requirements.
1)
ISO 9241-3:1992, Amendment 1:— , Annex C (normative): Visual performance and comfort test.
ISO 9241-5, Ergonomic requirements for office work with visual display terminals (VDTs)— Part 5: Workstation
layout and postural requirements.
ISO 9241-7, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 7: Requirements
for display with reflections.
ISO 9241-8, Ergonomic requirements for office work with visual display terminals (VDTs) — Part 8: Requirements
for displayed colours.
ISO 13406-2, Ergonomic requirements for work with visual displays based on flat panels — Part 2: Requirements
for flat panel displays.
1) To be published.
ISO 9241-9:2000(E)
3 Terms and definitions
For the purposes of this part of ISO 9241, the following terms and definitions apply. The illustrations of the devices
used in this clause do not necessarily represent the design requirements and recommendations of this part of
ISO 9241.
3.1 Actions
3.1.1
click
depression and release of a button or actuation point on an input device
3.1.2
drag
moving one or more objects on a display by translating it along a path determined by a pointer
3.1.3
free-hand input
input where the input device controls the movement of the cursor without any constraints following the manual input
of the user
3.1.4
pointing
operation with a graphic user interface in which an input device is used to move a small display image (such as a
pointer) to a specific location on the display
3.1.4.1
direct pointing
hitting a target unaided by system feedback
EXAMPLE By direct pointing with a finger or stylus.
3.1.4.2
indirect pointing
using system visual feedback to hit a target
EXAMPLE When the system is controlling a screen pointer in response to a mouse movement.
3.1.5
selecting
choosing one or more items on a display
3.1.6 Touch strategies
3.1.6.1
first-contact touch strategy
actuation of display area upon touching the display surface
3.1.6.2
last-contact touch strategy
actuation of display area upon withdrawing touch from the display surface
3.1.7
tracing
following the outline of an image by moving the cursor or input device over the lines or shape of an image
3.1.8
tracking
moving a pointer or predefined symbol across the surface of a display screen in order to follow a target
2 © ISO 2000 – All rights reserved

ISO 9241-9:2000(E)
3.2 Feedback
3.2.1
feedback
indicators (such as tactile, auditory or visual) sensed by a user of an action (such as movement or actuation of an
input device)
NOTE Display feedback refers to a change on the display resulting from an input device movement or activation.
3.2.1.1
kinesthetic feedback
action perceived by the mechano-receptors in joints, muscles, and tendons resulting in awareness of position,
movement, weight, and resistance of the limbs or other body parts
3.2.1.2
tactile feedback
indication of the results of a user action transmitted through the sense of touch
3.3 Hardware
3.3.1
button
mechanical object integrated into an input device, which responds to force when depressed, and provides input to
the computer
3.3.2
goniometer
instrument which measures the angle of the joints
3.3.3
input device
user-controlled device that transmits information to a system
3.3.4
joystick
lever mounted on a fixed base (see Figure 1) used to control the movement of objects displayed on a screen and
which controls the relationship between the force or movement applied to the lever and the movement of a pointer
Figure 1 — Side view of example of a joystick
3.3.4.1
displacement joystick
joystick with a lever that tilts in the direction of applied force from a home position moving the display pointer in
proportion to the displacement distance
ISO 9241-9:2000(E)
3.3.5
light-pen
light-sensitive input device that, when pointed onto a specific location on a display, identifies its position to the
system (see Figure 2)
Figure 2 — Example of a light-pen against a display
3.3.6
mouse
computer input device having one or more buttons and capable of two-dimensional rolling motion which can drive a
cursor on the display and performs a variety of selection options or commands
3.3.7
overlay
thin template on the surface of a tablet (see Figure 3) used to indicate the graphic functions available to the user
Figure 3 — Top view of example of a tablet with a graphic overlay (indicated by arrow)
3.3.8
palm rest
surface which supports the palm of the hand when using an input device (see Figure 4)
NOTE A palm rest is smaller than a wrist rest which provides support for both the palm and wrist, or the wrist only.
4 © ISO 2000 – All rights reserved

ISO 9241-9:2000(E)
Figure 4 — Top view and side view examples of palm rests used with mice
3.3.9
pointer
symbol on a display which indicates the input or selection position whose movement is controlled by an input
device
3.3.10
puck
hand-held device similar to a mouse but with a reticle view port and that is typically used with a digitizing tablet (see
Figure 5)
Figure 5 — Top view examples of two types of pucks
3.3.11
reticle
orthogonal lines in the lens of a puck used to visually align the puck to an image (see Figure 6)
Figure 6 — Top view of example of a puck with reticle (indicated in exploded view on left)
3.3.12
selector button
actuator located on an input device
ISO 9241-9:2000(E)
3.3.13
stylus
pen-shaped pointing device which, when touched to a display or graphics tablet (see Figure 7), can be used to
draw images on a display or select displayed objects typically by depressing the stylus tip or actuating a button
locatedalongthesideof the stylus
Figure 7 — Side view of example of a stylus over a graphics tablet
3.3.14
tablet
special flat surface with an input device (such as a stylus or puck) for selection, drawing, or indicating position of
images to be displayed (see Figure 3)
3.3.15
touch-sensitive screen (TSS)
input device that produces a position and selection input signal from a finger touching, lifting off, or moving across a
display
3.3.16
trackball
ball in a fixed housing that can be rolled in any direction by the fingers to control pointer movement, and that often
has adjacent buttons (see Figure 8)
Figure 8 — Example of top view of a trackball device with buttons
3.3.17
workstation
assembly comprising display equipment with or without a central processing unit, which may be provided with a
keyboard and/or input device and/or software determining the operator/machine-interface, optional accessories,
peripherals and the immediate work environment
[ISO 9241-5:1998]
6 © ISO 2000 – All rights reserved

ISO 9241-9:2000(E)
3.4 Measures
3.4.1
biomechanical load
effect of work posture and effort on the musculo-skeletal system
3.4.2
colour difference
difference between two colour stimuli, defined as the Euclidean distance between the points representing them in
the CIE 1976 L*u*v*
NOTE See ISO 9241-8:1997.
3.4.3
design reference posture
posture specified for the purpose of workstation design to define relative positions and dimensions
[ISO 9241-5:1998]
3.4.4
design viewing distance
distance or range of distances (specified by the display supplier) between the screen and the operator’s eyes for
which the images on the display meet the requirements of this part of ISO 9241, such as that character size, raster
modulation, fill factor, spatial instability (jitter) and temporal instability (flicker)
NOTE Adapted from ISO 9241-3:1992.
3.4.5
gain
relationship of the movement or change of an indicator on a display to the movement of a control
3.4.6
intended user population
groups of human beings for which a product or a workstation is designed
EXAMPLE Male and female workers of Southeast Asian origin aged between 45 and 65 years.
3.4.7
movement time
time to move a pointing device from a start position to a target position excluding stimulus presentation time and
button actuation time
3.4.8
parallax
difference in the apparent relative positions of objects when viewed from different points
3.4.9
resolution (resolving power)
smallest detectable movement, or actuation force, of an input device that results in a pointer displacement on a
display
3.4.10
task primitive
fundamental action (like pointing, selecting and dragging) associated with using a non-keyboard input device
NOTE User tasks contain a mix of task primitives.
3.4.11
throughput
measure of the rate of information transfer when a user is operating an input device to control a pointer on a display
NOTE Throughput is measured in bits per second.
ISO 9241-9:2000(E)
3.5 Posture
3.5.1
abduction of the arm
lateral moving or turning of the arm away from the body and position of arm and shoulder after this movement
3.5.2
adduction of the arm
lateral moving or turning of the arm towards the body, and position of arm and shoulder after this movement
3.5.3
deviation
moving or turning of the hand in its own plane away from the axis of the forearm, and position after this movement
3.5.4
displacement
change of position in the location of a point with respect to some reference coordinate
3.5.5
dorsal
pertaining to the back of the hand (see Figure 9)
Figure 9 — Dorsal view of hand
3.5.6
extension
moving a limb segment in the dorsal direction, and position of the segment and joint after this movement (see
Figure 10)
Figure 10 — Example of hand extension
3.5.7
flexion
moving a limb segment in the ventral direction (for example, moving the hand and fingers toward the palm) and
position of the segment and joint after this movement (see Figure 11)
8 © ISO 2000 – All rights reserved

ISO 9241-9:2000(E)
Figure 11 — Hand flexion
3.5.8
neutral posture
position that the body (and parts of the body) assumes when completely relaxed, that is, without any intentional
bending at the joints
3.5.9
palm
ventral area of the hand between wrist and base of fingers (see Figure 12)
Figure 12 — Palmar area (indicated by the circle) of the hand
3.5.10
pronation
medial rotation of the forearm (see Figure 13)
Figure 13 — Pronation (rotation indicated by arrow)
3.5.11
radial hand deviation
bending the hand at the wrist in the direction of the thumb (see Figure 14)
ISO 9241-9:2000(E)
Figure 14 — Radial hand deviation (direction indicated by arrow)
3.5.12
reach envelope
optimum or maximum space accessible to the intended user population with respect to a specified user position
3.5.13
supination
lateral rotation of the forearm (see Figure 15)
Figure 15 — Supination (rotation indicated by arrow)
3.5.14
ulnar deviation
bending the hand at the wrist in the direction of the little finger (see Figure 16)
Figure 16 — Ulnar deviation of hand (direction indicated by arrow)
10 © ISO 2000 – All rights reserved

ISO 9241-9:2000(E)
3.6 Usability indicators
3.6.1
effectiveness
accuracy and completeness with which users achieve specified goals
[ISO 9241-11: 1998]
3.6.2
efficiency
resources expended in relation to the accuracy and completeness with which users achieve goals
[ISO 9241-11: 1998]
3.6.3
satisfaction
freedom from discomfort, and positive attitudes of users towards the use of the product
[ISO 9241-11: 1998]
3.6.4
usability
extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency
and satisfaction in a specified context of use
[ISO 9241-11:1998]
4 Guiding principles
4.1 General
This clause describes basic ergonomic principles that apply to all input devices and are the basis for the general
and specific requirements and recommendations given in clause 6.
4.1.1 Appropriateness
An appropriate input device is effective, efficient and satisfactory for the tasks being performed and the intended
work environment.
NOTE Input device appropriateness may be enhanced by software.
4.2 Operability
4.2.1 Obviousness
The intended use of an appropriately designed input device for a task primitive is either obvious or easily
discovered.
4.2.2 Predictability
The use of an input device is predictable when it is designed to operate and respond according to the expectations
of the intended user population.
ISO 9241-9:2000(E)
4.2.3 Consistency
The use of an input device is consistent when it operates and responds in the same manner when used in similar
situations.
4.2.4 Compatibility
An input device is user compatible when its design accommodates anthropometric characteristics and
biomechanical capabilities of the intended users.
4.2.5 Efficiency
An input device is most efficient when it functions with the least amount of time and effort.
4.2.6 Effectiveness
A device is effective when its design takes into consideration factors that lead to enhanced or optimized user
performance by means of accuracy and completeness.
4.2.7 Feedback
An input device provides effective feedback when the user is given immediately perceptible and understandable
indication that the device is reacting to user actuation.
4.2.8 Satisfaction
An input device design is satisfactory when its design incorporates factors that lead to freedom of discomfort and
enhance positive attitudes of users towards its use.
4.3 Controllability
4.3.1 Responsiveness
An input device is considered to be responsive when feedback following its actuation is consistent and accurate.
4.3.2 Non-interference
An appropriately designed input device does not interfere with its own use; for example, the user's hand or arm
does not block an infrared beam and cables do not interfere with movement or control of the device during its
intended use.
4.3.3 Grip surface
Control of an input device is adequate when its grip and contact surface prevents unintended slipping during its
intended use.
4.3.4 Device access
Access of an input device is adequate when it can be grasped, positioned and manipulated quickly and easily
without adversely affecting performance.
NOTE The positioning of a device depends on its design, the design and adjustment of the workstation and the position of
the user.
12 © ISO 2000 – All rights reserved

ISO 9241-9:2000(E)
4.3.5 Control access
Access to input device controls is adequate when they can be located and actuated quickly and easily.
4.4 Biomechanical load
4.4.1 Postures
An appropriately designed input device can be operated by the user without undue deviation from a neutral
posture.
4.4.2 Effort
An appropriately designed input device can be operated without excessive effort.
4.4.3 User training
Users who are informed of the proper use of input devices, and make use of such information, can avoid excessive
effort and obtain improved performance.
5 Performance criterion
The input device shall be useable for its designated purpose. It is considered useable if users can achieve a
satisfactory level of performance on a given task and maintain an acceptable level of effort and satisfaction. This
objective is considered to be met when the guidelines in clause 4 are considered and the design requirements in
clause 6 are satisfied and recommendations considered.
6 Design requirements and recommendations
This clause contains design requirements and recommendations for the input devices addressed in this part of
ISO 9241.
6.1 General requirements and recommendations
Test methods to evaluate the conformance of normative requirements are described in clause 7.
6.1.1 Anchoring
If the input device is designed to be used for fine-positioning accuracy, it shall be possible to anchor some part of
the fingers, hand, wrist, or arm on either the input device or the worksurface to create a stable relationship between
the hand and the point of action.
6.1.2 Resolution
The input device should be designed for achieving a resolution that supports the precision required by the task
primitive. The overall resolution of a device is a result of the interaction between hardware and software.
6.1.3 Repositioning
If the use of the input device requires repositioning, then it shall be repositioned manually without the use of tools.
ISO 9241-9:2000(E)
6.1.4 Button design
6.1.4.1 Button activation
The input device should be designed to be resistant to inadvertent button activation during its intended use.
6.1.4.2 Button shape
Buttons should be shaped to assist finger positioning and button actuation.
6.1.4.3 Button force
Buttons should have a displacement force within the range of 0,5 N to 1,5 N until actuation.
NOTE Button force should be minimized without compromising usability.
6.1.4.4 Button displacement
Buttons intended to provide kinaesthetic feedback should have a minimum displacement of 0,5 mm. The maximum
displacement shall be 6 mm.
6.1.4.5 Inadvertent pointer movement
The input device should be designed such that inadvertent button actuation does not cause unintended movement
of the pointer.
6.1.4.6 Button lock
The input device shall be designed so that a hardware or software lock can be provided for buttons which need to
be continuously depressed for the duration of a task primitive such as, dragging, tracing, and free-hand input.
6.1.5 Consideration of handedness
Input devices should be operable by either hand; or right and left-handed devices should be available.
6.1.6 Pressure points
Input devices should be designed so that during use they do not cause pressure points that cause discomfort or
degrade performance.
6.1.7 Grasp stability
Grip surfaces should be of sufficient size, shape and texture to prevent slipping.
6.1.8 Access
The design of an input device should allow it to be located and be accessible within the user’s reach envelope.
6.1.9 Cabling
Cables attached to input devices should be located, or attached to, the input device such that they do not interfere
with use. The weight, flexibility, tension, and attachment location of the cable, and its potential to become
entangled, should be taken into account when designing cabling.
14 © ISO 2000 – All rights reserved

ISO 9241-9:2000(E)
6.1.10 Pointer movements
The relation between the movement of the input device and the movement of the pointer on a display shall follow
user expectations in cardinal directions.
6.1.11 Feedback
6.1.11.1 Event feedback
Feedback shall be provided for button actuation or data entry acquisition.
6.1.11.2 Signal speed
The feed forward signal from the input device to the system should occur within 20 ms.
NOTE Any delay in the hand/eye control loop is likely to cause loss of user performance. A delay of up to 20 ms does not
degrade user performance because it is usually not perceived. A delay of 40 ms results in a 10 % reduction in user performance
and a delay of 100 ms causes a 50 % reduction in user performance compared with a situation in which no perceptible delay
occurs.
6.1.12 Upper extremity and head posture
Input devices should be designed so that they can be operated without requiring undue deviations of the hand,
fingers, arm, shoulder and head from their respective neutral positions.
6.1.13 Shape and size
Finger, hand-held or grasped input devices should be designed to accommodate the hand size of the intended user
population.
6.1.14 Stability
The input device should be sufficiently stable, such that the accuracy of the input device should not be degraded
during normal operation.
NOTE Instability can affect performance, comfort and biomechanical load.
6.1.15 Surface temperature
The temperature of the device surface in contact with the user’s skin for contact periods of 10 min or more should
not be greater than 40 °C.
6.1.16 Consideration of parallax
Input devices (such as light-pens and touch screens) and software applications that are subject to parallax and
refractive displacement of target images should be designed to tolerate the user’s perception of target location due
to these optical characteristics.
6.1.17 Weight
The weight, and hence inertia, of the input device should not degrade the accuracy of the device during use under
a defined normal range of actions including translation, rotation, and button activation.
6.1.18 Gain
The gain of relative-positioning input devices should be appropriate to the task and should be user adjustable.
ISO 9241-9:2000(E)
6.1.19 Throughput
Input devices which are used for indirect pointing, selecting or dragging should be designed so that users can
achieve the throughput given in Table 1 within the range of task precision for which the device is intended. Input
devices should not reduce the functioning of muscles of the body extremity used for their control.
Table 1 — Examples of throughput for input devices controlled by
two different extremities
Controller Throughput
bit/second
Finger 3
Hand (wrist) 2
6.1.20 Maintainability
The input device shall be designed such that the user is able to clean or adjust the device without special tools.
6.2 Specific input device requirements and recommendations
6.2.1 Mice
6.2.1.1 Sensor location
The motion sensing point (such as the rolling ball on the underside of a typical mouse) should be located under the
fingers rather than under the palm of the hand.
NOTE The term “finger” includes the thumb.
6.2.1.2 Button motion
The device should be designed such that during its intended use the fingers should be able to make contact and
actuate buttons without excessive deviation from a neutral posture.
NOTE “Excessive” means, for example, interfering with accuracy or causing muscular strain.
6.2.1.3 Button actuation
It should be possible to press the buttons on the mouse without reducing control of the device.
6.2.1.4 Resolution consistency
The resolution of a mouse should be independent of both the position of the device on the worksurface and the
position of the pointer on the display.
NOTE However, the resolution may be changed by the software or the user.
6.2.2 Pucks
6.2.2.1 Button motion
The device should be designed such that, during normal use, the fingers should be able to make contact and
actuate buttons without excessive deviation from a neutral posture. See the note in 6.2.1.2.
16 © ISO 2000 – All rights reserved

ISO 9241-9:2000(E)
Button contact surfaces should be perpendicular to the displacement direction of the button and to the motion of
the finger during flexion.
6.2.2.2 Button actuation
It should be possible to press the buttons on a puck without causing unintentional movement of the device.
6.2.2.3 Reticle window
The reticle window should be sufficiently transparent and free of aberrations to allow appropriate legibility.
6.2.2.4 Reticle location
The reticle window should be designed and located on the puck to allow it to be operated without requiring the
user’s head to be excessively deviated (flexion) by more than 15�.
6.2.2.5 Unintended slippage
The puck should be resistant to unintended slippage if it is used on an inclined surface.
6.2.2.6 Target obstruction
The size of the input device should not visually obstruct the target on the viewing area to the extent that user
performance is impaired.
6.2.3 Joysticks
6.2.3.1 Actuation force
The force to displace finger-operated joysticks should be between 0,05 N and 1,1 N.
6.2.3.2 Displacement
For hand-operated displacement joysticks, the displacement should not exceed 45� in the left and right directions,
30� in the forward direction (away from the user), and 15� in the backward direction (towards the user).
6.2.3.3 Button location
The function buttons of a finger-operated joystick should be located on top of the handle so that the buttons can be
actuated by the index finger.
The function buttons of a hand-operated joystick should be located on the top or side so that they can be actuated
by the thumb, index or middle digit.
6.2.4 Trackballs
The factors to consider when selecting a trackball include
� pointer movement,
� precision required in the task, and
� ability to reposition fingers or thumb.
ISO 9241-9:2000(E)
6.2.4.1 Size
The chord length of the exposed area of the trackball should be at least 25 mm. The exposed arc, measured from
the centre of the trackball, should be not less than 100� and not greater than 140� (see Figure 17). The
recommended exposed arc is 120�.
Dimensions in millimetres
Key
1 Input device surface
Figure 17 — Chord length and exposed arc of a trackball
6.2.4.2 Rolling force
Therollingforceof atrackballshouldbe0,2N to1,5N.
6.2.4.3 Starting resistance
Thestartingresistanceshouldbe0,2N to 0,4N.
6.2.5 Tablets and overlays
NOTE For large digitizer tablets operated from a standing position, it is assumed that the user can move laterally in order to
allow the requirements and recommendations in this subclause to be met.
6.2.5.1 Tablet height and slope
The design of the tablet (height, depth and slope) should allow the user to adopt the design reference posture if the
tablet is incorporated into the workstation.
6.2.5.2 Tablet and overlay contact surface
The user contact surface of the tablet and overlay should be flat and smooth.
6.2.5.3 Tablet and overlay surface reflections
Reflections or glare from the tablet and overlay surface should not interfere with the visibility of imprinted images on
the tablet or overlay, nor reduce visual efficiency or comfort.
NOTE Overlay images can be imprinted onto tablets or be of removable material.
18 © ISO 2000 – All rights reserved

ISO 9241-9:2000(E)
6.2.5.4 Actuation force on tablet or overlay
For functions that require intermittent input against the tablet or overlay, the maximum force required for input
should not exceed 1,0 N.
6.2.5.5 Control display gain
The control display gain should be adjustable according to intended user needs and task requirements.
6.2.5.6 Legibility of legends and graphic symbols
All legends on the tablet and overlay shall be legible from the design viewing distance. Graphical symbols should
be identifiable from the design viewing distance.
6.2.5.7 Size of legends and graphic symbols
The nomenclature for the symbols, capital letters and numbers on a tablet and overlay shall have a minimum
perceived height of 16 � of visual arc at the design viewing distance.
The perceived height includes the user position.
The recommended perceived height is 20 � of visual arc.
6.2.5.8 Width to height ratio of legend
The ratio of the width of a capital letter (except capital i: I) to the height of the letter shall be between 0,5: 1 and 1: 1
of the character height.
6.2.5.9 Height to stroke width ratio of legend
The ratio of the height of a capital letter to its stroke width shall be between 5: 1 and 14: 1.
6.2.5.10 Contrast of legends and graphic symbols
Primary legends and symbols shall have a minimum luminance contrast ratio of at least 3: 1. A lower luminance
contrast ratio, for legends and symbols other than primary ones, is acceptable provided that colour differences
ensure that they are recognizable.
6.2.5.11 Colour of legends and graphic symbols
For colours that are intended to differentiate information, the colour difference should be obvious and easily
perceivable.
6.2.5.12 Function grouping
Groups of functions on an overlay or tablet should be easily and quickly distinguishable.
6.2.5.13 Overlay attachment
The overlay should be easily and simply attached to, and removed from, the tablet.
6.2.5.14 Unintended overlay movement
The overlay should not accidentally become detached from the tablet during normal operation.
ISO 9241-9:2000(E)
6.2.5.15 Overlay flatness
The overlay should be flat when placed on the tablet.
6.2.6 Styli and light-pens
6.2.6.1 Grasp surface
The grasp surface of the stylus and light-pen should be slip resistant.
6.2.6.2 Activation force
For continuous input using styli, the force requirements to activate the stylus on a tablet should be not greater than
1,5 N.
6.2.6.3 Selector button force
The activation force of the selector button should be between 0,3 N and 1,5 N.
6.2.6.4 Contact area of selector button
A selector button should have a contact surface that contains a circular area with a diameter not less than 5 mm.
6.2.6.5 Size
Cylindrical styli and lightpens should be between 120 mm and 180 mm in length and 7 mm to 20 mm in diameter.
6.2.6.6 Weight
Styli and lightpens should have a mass between 10 g and 25 g.
6.2.7 Touch-sensitive screens
6.2.7.1 Target location
Vertically oriented touch-sensitive screens shall allow touch targets to be positioned below shoulder height.
NOTE This means that a vertically oriented touch-sensitive screen is tiltable, moveable and height-adjustable so it can be
operated with the arm/elbow supported by the work surface and inside the reach envelope of the intended user population.
Horizontally oriented touch-sensitive screens shall allow touch targets to be positioned at or below elbow height
and inside the reach envelope of the intended user population.
6.2.7.2 Touch-sensitive area
For systems using a first contact touch strategy, the size of the touch-sensitive area should be at least equal to the
size of the ninety fifth percentile male distal (digit 2) joint breadth. The touch-sensitive area should be increased if
parallax results in a degradation in performance.
6.2.7.3 Character size and contrast
The area of the screen within the touch-sensitive location shall conform with the relevant requirements of
ISO 9241-3, ISO 9241-7, ISO 9241-8 and ISO 13406-2.
20 © ISO 2000 – All rights reserved

ISO 9241-9:2000(E)
6.2.7.4 Repeat function delay
When a repeat function is provided, there should be an initial delay of from 500 ms to 750 ms to prevent
unintended activation.
6.2.7.5 Inactive space of target
For touch-sensitive screens designed for first-contact touch activation, an inactive space of a width of at least 5 mm
should be provided around each touch target.
NOTE For touch-sensitive screens designed for last-contact touch actuation, the inactive space can be less than 5 mm.
6.2.7.6 Target tracking
During a drag operation, the object or pointer being moved should track the finger or stylus, both temporally and
spatially.
6.2.7.7 Static electricity
To avoid or reduce discomfort due to the discharge of static electricity when the us
...