Guidelines for Telecoms Accessibility - Printable Version

Technology Introduction

These guidelines cover fixed or mobile telecommunications devices and services delivered via Interactive Voice Response (IVR) systems. This includes the hardware and software aspects of public or private telephones and videophones and menu-based services such as voicemail.

If the product or service combines telecoms devices or services with other technologies, then also refer to the guidelines for those other technologies. For example, if a videophone application is hosted on a PC platform, you should also follow the Application Software Accessibility Guidelines.

Guidelines Introduction

Priority 1

Following priority 1 will ensure that the device or service can be used by most people with impaired mobility, vision, hearing, cognition and language understanding.

1.1 Ensure that all operable parts are reachable by people of all heights and people sitting in a wheelchair or buggy

The operable parts include such things as buttons and keypads, input slots for cards or money and dispensers for returned money and cards. Users should be able to access all of these from whatever position and orientation they find themselves in naturally when using the telephone. Preferably, this should be a single position which does not require the person to reorientate themself during operation.

Access to operable parts
Ensure that all operable parts are within reach.

Rationale

Users who are extremely short or who sit in a wheelchair have substantially less reach than average sized users who are standing up. If they have to overstretch to reach things, they may risk injury or, in extreme cases, may not be able to operate the telephone or collect their outputs. Whilst tall users can extend their reach by stooping, this could be embarrassing for extremely tall users who may find themselves having to bend or crouch a long way.

Provide a clear access path
Ensure easy access to the device for people using wheelchairs, buggies or mobility devices.

Wheelchair users may find it awkward to reorientate themselves during use if this involves swivelling in a confined or crowded space.

Wheelchair clearance and turning circle
A wheelchair user requires a corridor of 0.9m in width to access a device and a minimum of 1.5m to make a complete turn comfortably.

Directions and Techniques

Refer to anthropometrical data

Refer to appropriate physical design guidelines or building accessibility guidelines which give minimum and maximum heights and reach distances. The United Nations have a useful set of anthropometrical data covering ranges of height and reach when standing or sitting in a wheelchair, plus required path and turning space dimensions for wheelchairs.

Common reach zones
Ensure that users of all heights can reach all operable parts. The comfortable range is between 1.2m and 0.9m. The maximum acceptable reach height for wheelchair users is 1.4m.

How you could check for this:

Self-test early prototypes

Designers can run simple reach tests themselves at the initial design or prototype stage. Using a mock-up with the controls placed in their intended positions based on appropriate physical design guidelines, you can simulate short and tall people and wheelchair users by sitting in a chair, standing on a raised area or kneeling down. Whilst this will not be a replacement for proper testing with real user's, it will give some insight into what it is like to be reaching for controls from the users perspective and will help reveal any serious problems in the layout before further work is carried out. If standing on something, you should make sure it is sufficiently strong and stable and take care to avoid the possibility of injuries caused by falling off it.

Include user data in the design

If you are designing using a CAD package, it may be possible to include various simulated users as elements in the design, based on human anthropometrical data.

Test with real users

During development, you should test the prototype in a realistic situation with real people, particularly people who routinely use wheelchairs or motorised buggies.
About user testing

1.2 Ensure that displays are within sight of people of all heights and people sitting in a wheelchair or buggy

A "display" encompasses anything from a single line LCD display to a CRT monitors.

Being "within sight" means that the user's line of sight to the display is unobstructed at a distance and angle that enables the display to be read clearly by someone with 20:20 vision, within the environmental constraints such as ambient lighting (allowing for users with restricted vision is covered in other checkpoints). The display should be within sight from whatever position and orientation the user finds themselves in naturally when using the telephone. This will be different depending on the person's height and whether they are sitting in a wheelchair or motorised buggy.

Rationale

A display that is positioned for optimal viewing by users of average height may present difficulties for other non-average users. Users who are extremely short, extremely tall, or who sit in a wheelchair will be looking either up or down at the display and from further away. The increased distance may mean that fine text or information is difficult to read. The more acute angle may also affect readability by changing the aspect ratio. Or it may mean that other parts of the device get in the way.

Eye height ranges
Ensure that users of all heights can see displays. The standing eye height for the largest person (95th percentile) is approx. 1.8m. The standing eye height for the smallest person is approx. 1.35m. Wheelchair users often have eye heights as low as 1.15m.

A particular problem for people looking upwards at the display is the effect of reflected light. Some displays can be completely unreadable when a light source such as the sun is shining on them. Someone who is taller can often position their body between the light source and the display, making it easier to read.

Line of sight
Ensure that there is a clear line of sight to the display from a range of angles. Check for glare on the screen from a range of positions.

Directions and Techniques

Refer to anthropometrical data

Refer to appropriate physical design guidelines or building accessibility guidelines which give minimum and maximum heights. The United Nations have a useful set of anthropometrical data covering ranges of height and reach when standing or sitting in a wheelchair.

Reduce glare

Anti-glare displays can help reduce the problem of reflected light. The physical design of the telephone installation can also help by blocking light from reaching the display. However, be aware that anything that obstructs light from reaching the display may also obstruct the user's view.

Increase size

Increasing the size of text or other displayed information can help to make it more readable at an angle.

Consider adjustable or extra displays

In extreme cases, you may consider using height adjustable or rotatable displays or dual-display systems.

How you could check for this:

Self-test early prototypes

Designers can run simple sight tests on a prototype, simulating short and tall people and wheelchair users by sitting in a chair, standing on a raised area or kneeling down. Whilst this will not be a replacement for proper testing with real users, it will give some insight into what it is like to be viewing the display from the user's perspective and will help reveal any obvious problems before further work is carried out. If standing on something, you should make sure it is sufficiently strong and stable and take care to avoid the possibility of injuries caused by falling off it. Difficult lighting conditions are easily simulated by either using the prototype outside in sunlight or positioning artificial lights appropriately.

Include user data in the design

If you are designing using a CAD package, you may be able to simulate different viewing points before creating a prototype.

Test with real users

During development, you should test the prototype in a realistic situation with real people, particularly people who routinely use wheelchairs or motorised buggies.
About user testing

1.3 Ensure that controls are adequately sized and sufficiently spaced to be operated by people with limited dexterity

The user should be able to operate any control, such as a button, key or knob, without accidentally operating any other control at the same time. This means that each control should be sufficiently large for the user to target and activate it, even if they suffer from limited dexterity through lack of motor control or shaking hands. Precise activation should be possible even with shaking hands. Controls should also be sufficiently spaced out that the user does not accidentally activate two at once.

Rationale

Many, particularly older, users have reduced dexterity in their hands due to degenerative conditions that affect their muscle control or that cause uncontrolled movements such as shaking. Small controls can be difficult to operate for these users because they either cannot accurately target them or because the uncontrolled movements cause their hands to stray off them. This makes the telephone difficult to use.

In extreme cases, the user may accidentally strike the wrong button or key or strike two at the same time, causing errors. This can be particularly problematic with contact-sensitive controls where the user's hand may wander over the wrong area. The problem is made worse by the controls being closely spaced. Another problem may occur if controls require finely controlled activation, or offer little resistance, or positioning, or precise positioning of a rotary control.

Key and button design
Make buttons large and tactilely discernable. Leave at least 2.5mm between the keys.

Directions and Techniques

Make boundaries between controls clear

Clearly define the edges of buttons and keys, by clearly contrasting keys from background tone and colour, or using a ridged or other border which is darker or lighter than the control itself.

Space controls sufficiently

Leave a gap of at least 2.5mm between the edges of adjacent buttons or keys.

Shape the input slots

Payphones should provide a funnel-shaped entry to the card and coin input slots, or other slots, to help guide the items in.

Avoid difficult physical actions

Avoid operations that require more difficult physical actions such as fine positioning of rotary controls, pressing and rotating controls simultaneously, or time-limited actions such as pressing twice in quick succession.

Present enough of the output for the user to grasp

Ensure that outputs from payphones (such as returned coins and cards) are easy to retrieve. Cards should protrude at least 2cm from the slot surround.

Card and ticket protrusion
Ensure that cards and tickets protrude at least 2cm from the surrounding slot.

Allow user-selectable settings

Applying the previous techniques should result in telecommunications hardware which suits all users. However, in some cases, what is best for one group of users is not necessarily best for all.

If this is the case, it may help if the user interface can be adapted by the user, or even automatically for the user, to fit their individual capabilities. For example, the volume and pitch of audible outputs should be adjustable.The choice could be made by the user through manual adjustment. Alternatively, information required for the hardware to switch automatically could be encoded on a user's smart card or SIM card at their request.

How you could check for this:

Self-test early prototypes

Designers can run simple tests on an early prototype, although it is difficult to properly simulate low dexterity. One possible method is to try operating the prototype using a finger-shaped pointing stick rather than with your fingers. Because it will be more difficult to be accurate, you may get some idea if major problems are likely to occur. Another possibility is to try operating it while wearing workshop gloves. It would be possible to simulate a hand tremor by shaking the user's hand or arm or by shaking the prototype. However, you should take extreme care in doing either of these since both could be highly dangerous.

Test with real users

During development, you should test the prototype in a realistic situation with real people, particularly older people.
About user testing

1.4 Ensure that operation requires minimal strength, grip and wrist twisting

Using telecommunications hardware may require a number of physical operations - lifting handsets, pressing buttons or keys, turning knobs or other moving parts, inputting cards or other items and retrieving cards, tickets or other outputs. All these operations should be possible with minimal grip, pushing and pulling strength or twisting of the wrist.

Rationale

Many, particularly older, users have greatly reduced strength due to degenerative conditions that affect muscle power or restrict movements of the joints in the fingers, hands and wrists. Most telephones need to be gripped and most operations require finger or hand movements. If the handset is awkward, the controls too stiff, the phone card slot too narrow or the machine's grip on the card too tight, some users may not have the strength to overcome this and will be unable to use the device.

Directions and Techniques

Favour pressing, but with modest force

As far as possible, avoid using controls that have to be gripped and turned rather than pressed. Allow for a maximum pressing force of 5lbf.

Do not grip outputs too tightly

Ensure that the machine's grip on outputs such as returned phone cards is no more than is necessary to prevent them falling out or being pulled out by the wind.

Ensure handsets are light, well-balanced and ergonomically designed

Handsets should be easy to lift and hold for users with limited grip strength. It helps to have a gap between the handset and the base unit if there is one, so that the user can curl their fingers around the handset before picking it up. Handsets should also be designed to be easy to hold to the ear and mouth for people with limited wrist movement.

Avoid moving parts or design them carefully

Moving parts, such as antennas and flaps on mobile phones, should either be avoided or designed to be easy to use with one-hand, weak grip strength and limited dexterity.

How you could check for this:

Test with real users

To test for this, you should have a prototype used in a realistic situation by real people, particularly older people.
About user testing

1.5 Ensure that the device can be operated using only one hand

If a user has use of only one hand, they should still be able to operate all the functions of the telephone without requiring assistance.

Rationale

Users often have no use of one of their hands, either due to a physical disability or because they are using it to operate or hold onto something else, such as a computer keyboard, pen, child, shopping bag, physical support or a purse containing their valuables. It should still be possible for them to use the telephone without having to let go of any of these things.

Directions and Techniques

Ensure that all parts can rest on a level surface

For telephones consisting of a base unit containing the keypad and a separate handset, it should be possible to rest the handset on a level surface while dialling a number on the keypad. It should also be possible to leave the base unit on a level surface While using the handset.

How you could check for this:

There are no specific test methods recommended for this guideline.

1.6 Ensure that users with restricted or no vision can use all functions of the device

Users will normally access the functions of a telephone through controls such as buttons, keys and knobs. These may or may not be visible to users who are blind, partially sighted or colour blind. However, all users with restricted vision must still be able to use all the functions. Where possible, the controls should be designed so that users who have partial vision or colour blindness are able to perceive them, understand what each is for and know how to operate them. It may also be possible to design in such a way that users who are completely blind can still perceive, distinguish and operate the same controls. If this is not possible or extremely difficult, an alternative control method should be made available which these users can perceive and which can be used to access the full functionality.

Rationale

Control labels, prompts and delivered information are often provided as text but presented visually. Any user who cannot see to read the text will not be able to perceive the information it contains. The controls themselves have first to be perceived by the user before they can be operated. Again, this often relies on sight, so that people with restricted sight may be unable to use the telephone.

Directions and Techniques

Consider developing an audio menu

If the telephone interface relies on visible correlations between changing prompts and unlabelled buttons, as on many mobile phone interfaces, users may still not be able to identify which button is associated with each prompt. In this case, it may be best to develop a separate audio menu which prompts the user to press a number on the keypad for each choice. This can be done along the lines of Interactive Voice Response (IVR) systems which ask the user to "press 1 for this option, press 2 for that option" etc. This can be achieved using either pre-recorded audio or speech synthesis. Speech synthesis, whilst more flexible, is often of much poorer quality and may be difficult to understand for some users and in noisy environments.

Allow voice input

Voice recognition software can be used to enable users to choose functions by speaking the name and dial numbers by speaking the number.

Consider label text, colour and contrast

For label text, ensure that characters are at least 4mm high but avoid using all upper case which is more difficult to read than mixed case. For good contrast, use light coloured characters on a dark background, e.g. White or yellow on matt black or a dark colour. Avoid using pale colours or patterned backgrounds for text. Also avoid red on green or yellow on blue since these combinations may cause problems for people who are colour blind. Use a typeface designed for display, such as Tiresias, which has numerals with open shapes which are easier to distinguish for people with low vision.

Do not rely on colour for meaning

Whilst colour coding can be useful as an aid to recognition, it should not be relied on entirely, since over 8% of Irish males and some females have difficulty distinguishing between red and green (other forms of colour blindness are relatively uncommon).

Add tactile indicators to buttons and keys

It is standard practice to put a single raised dot on the 5 key to help users orientate their fingers on the keypad by touch. It is also possible to emboss Braille on keys and buttons, although this is not as widely effective as it may seem, since less than 2% of visually impaired people can read Braille. Also, Braille has less value in outdoor situations during cold weather, because tactual sensitivity is dramatically reduced at lower temperatures.

Key and button design
Make buttons large and tactilely discernable.

Follow standard layouts for keypads

Visually impaired users rely on telephone keypads following the standard layout for numerals, # and * keys.

Raise or recess buttons and keys

Raise or recess the buttons and keys by at least 2mm over the surrounding area.

Provide tactile and audio feedback

Provide tactile and audio feedback to indicate the operation of controls. Tactile indication can be provided by requiring a gradual increase in the force to activate a control, followed by a sharp decrease as it is activated. Audio feedback can be given using a beep or click. For multiposition controls, feedback should be used to indicate the current position or status.

Raise the edges of input slots

Design a raised ridge around input slots such as those used for entering a card or plugging in a headphone jack. This will make them easier to locate by touch.

Allow user-selectable settings

Applying the previous techniques should result in a device which suits all users. However, in some cases, what is best for one group of users is not necessarily best for all. If this is the case, it may help if the user interface can be adapted by the user, or automatically for the user, to fit their individual capabilities. For example, users who are visually impaired could choose voice output and large type, whilst users with good vision may prefer to have more detail and no sound. The choice could be made by the user selecting from a number of displayed options. Alternatively, information required for the device to switch automatically could be encoded on a user's smart card or SIM card at their request.

How you could check for this:

Self-test early prototypes

Designers can run simple sight tests themselves on an early prototype, by simulating various types of vision loss. Complete loss of sight can be simulated either by wearing a blindfold, turning off the lights or putting the device in a black bag. To simulate partial sight, a test user who normally wears glasses could take them off. It is also possible to buy low vision simulation glasses which simulate various types of visual impairments. In all cases, extreme care should be taken to avoid injury through loss of balance or collision with unseen objects. This may require that the test user remains seated or, if they have to move around, obstacles such as floor cabling are removed in advance. Although this type of ad hoc testing will not replace proper testing with real users, it will give some insight into what it is like to be operating with reduced vision.

Test with real users

1.7 Ensure that all outputs under the control of the device can be perceived by users with restricted or no vision

Users who are blind, partially sighted or colour blind should be able to perceive all of the outputs from the device. The outputs include any information that is presented and any physical items that are delivered, such as returned cards and cash. This does not include the content of the communication itself, such as the caller's voice or gestures, since that is not under the control of the device.

Where possible, visually displayed information should be delivered in a form that users who have partial vision or colour blindness can see. Where this is not possible, or for users who are completely blind, an alternative form that they can perceive should be made available and it should provide the same information.

Visually impaired users should also be able to notice when any delivered outputs have appeared and where. Preferably, they should be able to anticipate exactly when and where the delivered outputs will appear, so that they can be ready to grasp them as soon as possible.

Rationale

Information output is usually provided as text and presented visually. Any user who cannot see to read the text will not be able to perceive the information it contains. Not being able to see text well enough to read it is often due to a combination of poor vision, inadequate text quality and poor lighting. So by increasing the legibility of the text or the lighting, even users with some visual impairment will be able to read and understand it.

Take steps to reduce glare
Ensure that when the device is installed the screen is visible to those both seated and standing.

Movement reduces legibility and some users who can read quite well are nevertheless unable to read the same text if it is moving.

Often the only way the user knows something has happened is by listening to incidental noises, such as the whir of the motor in a card slot. Even users who are totally blind can gather information about the outputs by listening for these noises. Although these noises are incidental, similar sounds can be included intentionally, ranging from simple clicks and beeps to spoken alerts.

When information outputs are displayed visually as written text, non-sighted users will need to be able to hear it spoken, although care should be taken not to compromise the user's security.

Directions and Techniques

Add voice output

Add voice output to speak any information that is displayed visually. This can be achieved using either pre-recorded audio or speech synthesis. Speech synthesis, whilst more flexible, is often of much poorer quality and may be difficult to understand for some users and in noisy environments. If voice output is likely to be intrusive or if the information is of a sensitive personal nature, allow the audio to be turned off during a user session and provide a standard jack socket for connecting an earphone. Inserting a jack plug should switch off the output to the external loudspeakers.

For all visual cues, provide corresponding audible cues

Supplement visual cues, such as flashing indicator lights, with simultaneous corresponding audible cues, such as clicks, beeps and spoken alerts.

Provide audible indication of phone and network status

It should be possible to tell the status of the telephone (on, off, ready, charging, dialling, etc.) without requiring vision. This can be done using either beeps or spoken announcements.

Consider text size, contrast and typeface

Ensure that characters are at least 4mm high but avoid using all upper case which is more difficult to read than mixed case. For good contrast, use light coloured characters on a dark background, e.g. White or yellow on matt black or a dark colour. Avoid using pale colours or patterned backgrounds for text. Also avoid red on green or yellow on blue since these combinations may cause problems for people who are colour blind. Use a typeface designed for display, such as Tiresias, which has numerals with open shapes which are easier to distinguish for people with low vision.

Avoid using scrolling text

Some visually impaired users find it difficult to focus on moving text.

Do not rely on colour for meaning

Do not rely on colour for meaning
The buttons on this web page rely on the users ability to distinguish between red and green.

Provide adequate lighting and take steps to reduce glare

Most text displays use CRTs, LEDs or backlit LCDs so they provide their own light source. They should have enough power to provide a clear contrast between the light and dark areas in all conditions. If this is not the case, the display will have to be adequately illuminated form an external source.

Anti-glare displays can help reduce the problem of reflected light which reduces text legibility. The physical design of the casing can also help by blocking direct or reflected light from reaching the display. However, be aware that anything that obstructs light from reaching the display may also obstruct the user's view.

Allow user-selectable settings

Applying the previous techniques should result in a device which suits all users. However, in some cases, what is best for one group of users is not necessarily best for all. If this is the case, it may help if the user interface can be adapted by the user, or automatically for the user, to fit their individual capabilities. For example, users who are visually impaired could choose voice output and large type (on telephones with digital displays), whilst users with good vision may prefer to have more detail and no sound. The choice could be made by the user selecting from a number of displayed options. Alternatively, information required for the telephone to switch automatically could be encoded on a user's smart card or SIM card at their request.

How you could check for this:

Self-test early prototypes

Designers can run simple sight tests themselves on an early prototype, by simulating various types of vision loss. Complete loss of sight can be simulated either by wearing a blindfold, turning off the lights or putting the telephone in a black bag. To simulate partial sight, a test user who normally wears glasses could take them off. It is also possible to buy low vision simulation glasses which simulate various types of visual impairments. In all cases, extreme care should be taken to avoid injury through loss of balance or collision with unseen objects. This may require that the test user remains seated or, if they have to move around, obstacles such as floor cabling are removed in advance. Although this type of ad hoc testing will not replace proper testing with real users, it will give some insight into what it is like to be operating with reduced vision.

Test with real users

During development, you should test the prototype in a realistic situation with real people who have various forms of visual impairment. In particular, you should include people who are recently impaired and have not yet developed enhanced perception or coping methods. This is the only way to find out if your audio equivalents can be understood by users well enough to provide the intended information.
About user testing

1.8 Ensure that videophones provide accurate reproduction of text and sign language

Screen size and image quality must be of a sufficient standard to support lip-reading, sign language interpretation and textual communication.

Rationale

Videophones can be particularly useful for those with hearing impairments, who can communicate using lip reading, sign language and text. However, if the display quality is not good enough to clearly distinguish lip movements, gestures and text characters, the communication will not be possible.

Directions and Techniques

Ensure screen resolution is sufficient

The screen resolution should be sufficient to render sign language and enable accurate lip-reading. At least 176x144 pixels and preferably 352x288 or more pixels.

Ensure transmission capacity is sufficient

To support lip-reading and sign language the picture update rate should be high enough for vivid signing and smooth movement reproduction, including finger spelling. This will require at least 12 pictures per second and preferably 21 or more pictures per second. This is not currently possible using PSTN (Public Switch Telephone Network). At least dual channel ISDN is required, allowing 128 kbps, and preferably six channel ISDN, allowing 384 kbps.

Ensure a minimal picture delay

The delay between the actions of the person at one end and the display of those actions at the other end should be less than 0.8 seconds, and preferably less than 0.4 seconds. This allows for fluid turn taking in conversation.

How you could check for this:

There are no specific test methods recommended for this guideline.

1.9 Ensure that all outputs under the control of the device can be perceived by users with restricted or no hearing

Users who are deaf or hard of hearing should be able to perceive all of the outputs from the device. This does not include the content of the communication itself, such as the caller's voice or gestures, since that is not under the control of the device.

Where possible, audible information, such as a ring tone, should be delivered in a form that users who are hard of hearing can hear. Where this is not possible, or for users who are profoundly deaf, an alternative form that they can perceive should be made available and it should provide the same information.

Rationale

Many telephone users, particularly those using assistive technologies, may use the telephone network despite hearing related disabilities.

If audio output in the form of spoken language is used to present information, users who cannot hear well enough to understand what is said will not be able to perceive the information being given. Not being able to hear audio outputs well enough to understand them is often due to a combination of poor hearing, inadequate sound quality and background noise. So by increasing the sound quality and taking steps to reduce background noise, even users with some hearing impairment will be able to understand the spoken information.Often, telephones rely on intentional sounds such as beeps and chimes or incidental sounds such as motor noises and coins being dispensed to inform the user that something has happened. This is particularly the case for outputs from public payphones for example. If there is no corresponding visual indicator, users who cannot hear the sounds may be unaware that something is happening or that an output has occurred.

Directions and Techniques

Provide adequate quality sound

Speech output of telephone functions and information can be achieved using either pre-recorded audio or speech synthesis. If possible, use digitised pre-recorded speech which has been recorded in a professional studio and spoken by a trained announcer. Speech synthesis, whilst more flexible, is often of much poorer quality and may be difficult to understand for some users and in noisy environments.

Take steps to screen out background noise

Baffles or sound absorbing materials can be built into the handset casing. Audio output can be provided via a headset or earpiece. Ensure that all telephones are compatible with such devices. If audio output is provided via an audio transducer held to the ear, provide a means for effective wireless coupling to hearing aids. Mouthpiece microphones can include sidetone reduction to reduce the problem of ambient noise picked up by the microphone mixing with the incoming speech.

Allow the user to increase the sound level

Allow users to increase the sound level by up to 20dB. Ensure that all audible outputs are adjustable both in terms of volume and pitch and include both high and low frequencies in ring-tones etc.

For all audible cues, provide corresponding visual cues

Supplement audible cues, such as clicks, beeps and spoken alerts, with simultaneous corresponding visual cues, such as flashing indicator lights.

Provide visual and tactile indication of incoming calls

Users should be notified of incoming calls using visual and/or tactile signals. For fixed phones, a flashing light is the best methods. For mobile phones, which are often out of vision in a pocket or bag, vibration should also be used.

How you could check for this:

Self-test early prototypes

Designers can run simple hearing tests themselves on an early prototype, by simulating various degrees of hearing loss or environmental conditions. Wearing earplugs, industrial ear protectors or noise-cancelling headphones can considerably reduce all sound, although it is difficult to reach complete loss of hearing.Partial hearing loss may be even more difficult to simulate accurately, since the degradation is often not uniform across the frequency range. It may be greater at some frequencies, particularly the high or low ends of the hearing spectrum.To simulate noisy environments, it is best to test the prototype in situ if this is practical. Otherwise, recordings of background noise from typical environments can be used.In all cases, care should be taken when running these tests since the user whose hearing is reduced may not be able to hear other important sounds, such as verbal warnings from experimenters, alerts, or fire alarms.

Test with real users

During development, you should test the prototype in a realistic situation with real people who have various forms of hearing impairment and use a variety of assistive technologies. In particular, you should include people who are recently impaired and have not yet developed enhanced perception or coping methods.
About user testing

1.10 Ensure compatibility with assistive technologies

Users with impairments often use assistive technologies to enable them to provide inputs and perceive outputs. These include additional earpieces, hands-free kits, hearing aids and text-based terminal systems.`

Telecommunications devices should be able to connect with assistive technologies, detect input from them and generate outputs in a way that they can detect.

Rationale

Many users have impairments that cannot be overcome solely within the design of the telephone itself. For these users, it is imperative that whatever technologies they use can be integrated with their telephone. This includes both technologies designed specifically for this purpose, such as text terminals and head-sets, and other general assistive technologies, such as hearing aids. If users are unable to use their normal assistive devices, they may be unable to use the telephone.

Directions and Techniques

Enable coupling to a hearing aid

There are a number of ways of coupling a telephone to a hearing aid, including inductive coupling, infra-red, direct electrical connection, or by matched acoustic transducers.

International standards relating to coupling of telephones earphones to hearing aids include:

ETSI (European telecommunications Standards Institute) ETS 300
ITU (International Telecommunication Union) ITU-T P.370

The European Telecommunications Standards Institute (ETSI) symbol

European Telecommunications Standards Institute (ETSI) symbol
Symbol for systems that facilitate people with impaired hearing.

Provide input and output sockets

A standard output jack socket will enable users to connect an earphone or headset. Provision for two handsets will enable a user to listen with both ears or a second person to listen in and relay what is said using sign language or by repeating the message so that it can be lip read.

Input sockets can be provided for external plug-in keyboards or for coupling to a computer, which can be used as a text terminal, for dialling or as a personal phonebook.

How you could check for this:

There are no specific test methods recommended for this guideline.

1.11 If using telephone cards, ensure that the card can be inserted into the card reader in its correct orientation without requiring vision

The user should be able to distinguish a phone card from other similar cards, turn it the right way round and insert it into the reader without being able to see the card or the reader. If the card is still inserted in the wrong orientation, it should be immediately rejected and the user should be notified of the error and allowed to try again.

Rationale

In your wallet or purse, you probably have a number of different cards for identifying yourself to different authorities or operating different machines or doorways. Often, the only distinguishing features on the cards are visual - the colours and what is written on each card. Ask yourself "if it was dark or I was unable to see, how would I know which card to use?".

Having retrieved the required card, you will normally have to put it into a slot or run it through a swipe card reader in a particular orientation and direction. Ask yourself "how would I know which side is which and which end is which? And even if I knew, how would I know which end should go into the slot or past the reader and which side should be up or down or to the left or right?". The answer will usually have something to do with looking at both the card and the slot or reader.A user who has poor or no vision or who is working in a dark place will have none of this information and will therefore have to resort to trial and error. If they choose the wrong orientation, they may be able to try again until they get it right. If they choose the wrong card, they may be in a much worse situation.

Directions and Techniques

Distinguish phone cards with tactile markings

Incorporate an embossed capital letter at least 10mm high with an embossing of at least 0.7mm. Note that, whilst Braille may seem a more obvious solution for tactile marking, less than 2% of visually impaired people can read Braille.

Incorporate an orientation notch on the card

A 2mm notch on the trailing edge of the card will enable the user to correctly orientate it for insertion into a horizontal slot by touch. This follows the CEN standard EN 1332 (Machine readable cards, related device interfaces and operations. Part 2 Dimension and location of tactile identifier for ID1 cards). Note that the slot should also be orientated in a way that fits the standard.

CEN 1332 card
CEN 1332 compliant card layout. The notch on the trailing edge helps visually impaired users to orientate the card.

Allow the card to be inserted in any orientation

If possible, the card reader could be designed so that the card can be inserted or swiped in any direction and with either side uppermost or leftmost. This will remove the possibility of errors. It does not, however, mean that there is no need to add an orientation notch on the card, since users who do not realise that any orientation is acceptable will then be unsure of what to do.

Generate an audible error indication when the card is inserted in the wrong orientation

If the card is inserted in the wrong orientation, immediately reject it and notify the user of the error using an audible indicator such as a low beep which suggests failure. Then allow the user to try again.

Consider using contactless cards

Contactless cards work at a distance. They do not need to touch the reader device or to be placed in any particular orientation. The maximum working distance is typically no more than 10cm for security reasons. Other types of cards include those that must be pressed onto a pad but can be in any orientation.

Consult international standards

International standards relating to card systems include:

CEN (Comite Europeen de Normalisation) EN 1332 & EN 726
ISO (International Standards Organisation) 7816 & ISO/IEC 10536
ITU (International Telecommunication Union) ITU-T E.118 & E.133

How you could check for this:

Self-test early prototypes

Designers can run simple tests themselves on an early prototype, by simulating sightless use. This can be done either by wearing a blindfold, turning off the lights or putting cards in a black bag. If working blindfolded or in the dark, extreme care should be taken to avoid injury through loss of balance or collision with unseen objects. This may require that the test user remains seated or, if they have to move around, obstacles such as floor cabling are removed in advance.

Test with real users

During development, you should test the prototype in a realistic situation with real people who have complete visual impairment. In particular, you should include people who are recently impaired and have not yet developed enhanced tactile abilities.
About user testing

1.12 Use the simplest language possible for instructions and outputs and, in visual displays, supplement it with pictorial information or spoken language

The language that is used for things like operating instructions, button labels, Interactive Voice Response (IVR) or voicemail menus and displayed information should be clear, unambiguous and easily digested. It should not contain unnecessary jargon, colloquialisms, idiomatic expressions or convoluted grammar. In displays, use explanatory icons, pictures or diagrams where possible to aid understanding and provide for written text to be spoken for the benefit of users who have difficulty reading.

Rationale

Many people find it difficult to understand complicated written text. Overall, 25% of the Irish population are "functionally illiterate", meaning that, while they can read to some degree, they would have difficulty reading a newspaper, filling in a form or following the instructions on a medicine bottle. People whose first language is not English, such as first generation immigrants or foreign visitors, may have poor understanding of spoken or written text.

Literacy is also a problem for people who are deaf. A 1993 NRB survey found that 80% of deaf adults in Ireland had the reading age of an 8-9 year old. This is due to the difficulties of learning through sign language, which has a different grammar and structure to spoken or written language, or by lip reading.

There are various cognitive impairments, the best known being dyslexia, which also cause difficulty in reading complicated written text.

Directions and Techniques

Keep it simple

The main technique is to keep it simple. Use everyday, jargon-free explanations. Avoid idiomatic expressions such as "on the one hand". Avoid long sentences by writing directly and concisely. You will often find that phrases like "on the one hand" are mere padding and can be removed without changing the meaning of the sentence. It is best if all instructions and information are written by experienced professional technical writers.

Supplement written instructions with audio

People who cannot read are often perfectly able to understand the same text if it is spoken. This can be achieved using either pre-recorded audio or speech synthesis. Speech synthesis, whilst more flexible, is often of much poorer quality and may be difficult to understand for some users and in noisy environments.

Supplement written instructions with pictures

Icons and diagrams can convey large amounts of information in an easily and quickly digested form. This may be the only medium that can be understood by people who are deaf and have poor literacy. Icons should be used in conjunction with written text rather than replace it altogether.

Allow user-selectable settings

Applying the previous techniques should result in a telephone which suits all users. However, in some cases, what is best for one group of users is not necessarily best for all. If this is the case, it may help if the user interface can be adapted by the user, or automatically for the user, to fit their individual capabilities. For example, some users may wish to choose spoken output, graphical buttons or fewer choices, whilst others may prefer to have only written text and more detail. The choice could be made by the user selecting from a number of displayed options. Alternatively, information required for the device to switch automatically could be encoded on a user's smart card or SIM card at their request.

How you could check for this:

Test with real users

Try to ensure that all instructions and information are covered in the user tests which should include users who have low English literacy, preferably for a number of different reasons (education, nationality, hearing or cognitive impairment).
About user testing

1.13 Do not cause the display to flash at a frequency of above 2Hz

Avoid all flickering or flashing with a frequency of more than twice per second. This includes flashing backgrounds or text, repeatedly turning graphics on and off or cycling between different images.

Rationale

Displays which flicker or flash can cause photosensitive epileptic seizures in susceptible individuals, particularly if the flash has a high intensity and is within the frequency range between 2 Hz and 60 Hz.

Directions and Techniques

There are no specific techniques recommended for this guideline.

How you could check for this:

There are no specific test methods recommended for this guideline.

1.14 Ensure that users can get to the device along an unobstructed path and operate it from a stable position

The path to public telephones must be free from obstacles such as steps, bins or signage that would obstruct the progress of users who are either walking or using a mobility aid such as a wheelchair or motorised buggy. This includes the path into any room or area containing the telephone. The user should be able to operate the telephone from a clear, flat area large enough to manoeuvre mobility aids such as a wheelchair or buggy.

Rationale

Users with restricted mobility who use wheelchairs, motorised buggies or walking frames may have difficulty getting around obstacles placed in the path to the telephone. Steps can cause particularly severe or insurmountable problems. In order to operate the telephone they will have to manoeuvre themselves to be close enough to it. Then when they have finished they will have to manoeuvre themselves out again, preferably without having to go backwards.

Having reached the telephone, users will need a stable platform from which to operate it.

Directions and Techniques

Provide a shallow ramp rather than steps

If it is necessary to raise the operating area above normal street or floor level, provide a ramp with a maximum slope of 6%.

Provide a clear, level operating area large enough to turn a wheelchair or buggy

Provide a clear area of 1.5 metres radius directly in front of the telephone, with a floor surface that is level in a direction parallel to the facia of the telephone. The gradient of any crossfall should not exceed 1 in 20.

Wheelchair clearance and turning circle
A wheelchair user requires a corridor of 0.9m in width to access a device and a minimum of 1.5m to make a complete turn comfortably.

Refer to anthropometrical data

Refer to appropriate physical design guidelines or building accessibility guidelines. The United Nations have a useful set of anthropometrical data covering required path dimensions for wheelchairs.

How you could check for this:

There are no specific test methods recommended for this guideline.

1.15 For Interactive Voice Response (IVR) systems, provide an equivalent service through an accessible channel for users who still cannot use the system

If an IVR service meets all the applicable priority 1 guidelines and there are still people who cannot use it, you should ensure that the services it provides are available through an alternative channel. Accessing the alternative channel should involve a minimal amount of inconvenience to the user and should be provided at no extra cost.

Rationale

Having met all the previous priority 1 guidelines, there may still be a small group of people who cannot use an IVR service. If this is the case, they are likely to be users who either have extreme difficulties in one particular area or who have multiple difficulties so that no combination of the accessibility features meets their needs.

For example, users who are deaf rely on TTY devices (text telephony which enables two-way typing over phone lines). This does not have to be supported under priority 1 of these guidelines. However, these users may still need to use the services that the IVR system provides.

Providing an alternative channel through a human customer service agent has particular benefits, even for customers who can physically use the system but have some difficulty with it. The human representative is able to interpret customers' requirements, answer their questions and give spontaneous information that the machine is not capable of. They also provide a 'face' to the organisation, which some users are far happier with.

Directions and Techniques

Use trained customer service agents

The best alternative service is through a trained customer service agent who will be able to deal with a wide variety of situations and needs in an intelligent way, something no machine can match. These agents may use TTY devices to communicate with customers. Although they should offer the same choices and deliver the same information as is provided by the IVR system (taking into account customers' personal security considerations), they may not be word-for-word, since the medium is different. If possible, designers should consult with TTY users to determine what is best.

How you could check for this:

There are no specific test methods recommended for this guideline.

Priority 2

Following priority 2 will make it easier to use and will include more people with cognitive impairments or multiple disabilities.

2.1 Allow sufficient time to accommodate the slowest users

Operations such as choosing from a list of options or inputting information should not be cancelled or interrupted by system prompts until even the slowest users have had sufficient time to complete the operation. This applies equally to telephone interfaces and Interactive Voice Response (IVR) or voicemail services.

Rationale

Completing a task can require users to carry out a number of separate activities. These may include listening to or reading prompts and instructions, understanding prompts and instructions, choosing the appropriate action, recalling information and making inputs. Each of these activities will take some time. Different users will require different amounts of time, depending on their abilities and confidence.

For spoken instructions, users who have poor hearing may have to listen to them very carefully a few times before they can understand them fully. For written instructions, users who have poor reading skills or have difficulty understanding written text may have similar problems.

Choosing the appropriate action will take longer for users who have an intellectual impairment. Confusion sometimes results if the user has even minor or temporary cognitive limitations. Navigating menu systems may be particularly difficult for people with cognitive impairments.Recalling information such as PIN numbers or personal details is more difficult for many older users or people who are tired or stressed.Making inputs by selecting phone keys or pressing buttons can take much longer for users who have physical difficulties.It can be very frustrating to be constantly prompted to complete a task and the stress that this can cause makes it even more difficult for the user. Ultimately, the worst thing is to be timed out after a lengthy process and asked to start again.

Directions and Techniques

Allow up to 10 times the average response time in order to accommodate the slowest users

To accommodate the slowest users, a good rule of thumb is to allow up to 10 times the average response time for each individual activity - listening, understanding, choosing, recalling information and making inputs. Use timeouts only where necessary and reminders only where helpful.

Use a dial-out buffer

A dial-out buffer is a memory buffer that holds a number until a Dial or Send key is pressed. This enables the user to take as long as they need to enter the number and to dial it when they are ready.

Allow user-selectable settings.

Applying the previous techniques should result in an interface that suits all users. However, in some cases, what is best for one group of users is not necessarily best for all. If this is the case, it may help if the interface can be adapted by the user, or automatically for the user, to fit their individual capabilities. For example, users who need more time to read, listen, think and act could choose longer timeouts and no reminders, whilst users who are quick may prefer to have shorter timeouts for security. The choice could be made by the user selecting from a number of displayed options. Alternatively, information required to switch automatically could be encoded at the user's request in their user profile or on a smart card or SIM card.

How you could check for this:

Gather time-to-task data

During user tests or after a first release, it is possible to gather data from a broad range of users about how long they take over each activity - reading and understanding, choosing, recalling information and making inputs. This can then be used to produce more accurate rules determining how long to allow. However, this should only be done by trained statisticians and the amount of data required for statistically significant calculations will be quite large.
About user testing

2.2 Ensure that the user interface and task flow is similar across different functions and remains the same across repeated visits

A uniform presentation and interaction style should be used for all functions of the device or service. This should not change between visits. This applies equally to telephone interfaces and Interactive Voice Response (IVR) or voicemail services.

The steps required to complete a task should also remain the same between visits. This includes the instructions, the choices provided, what inputs are required and how these are made.Having completed one task, the user should be able to complete a second task by carrying out a similar sequence of steps. Having carried out a task once, the user should be able to repeat the task by carrying out the same sequence of steps.

Rationale

People with cognitive or learning disabilities find it difficult when the interaction style or task flow varies. Consistency helps enormously by making procedures easier to understand and enabling users to transfer the skills learnt on one task to other tasks. If there is no consistency between tasks or, even worse, if there is no consistency over time for a given task, users will have to repeatedly relearn the procedure.

Directions and Techniques

Define and follow a standard style.

Consistency is achieved by defining a standard style and following it. This can outline standards for aspects such as colours, control sizes, positioning of controls and menu items, task order, navigation options and writing or speaking style for instructions and information. Standards should be written down in the form of a style guide. One or more members of the development team should be assigned to act in a quality assurance role, reviewing the design to ensure that it adheres to the style guide.

For IVR systems and voicemail services, it may be possible to enforce the standard automatically, by using templates or some kind of content management system.

Do not insert extra steps into a process

Avoid inserting extra steps into the sequence, such as advertising or promotion messages.

How you could check for this:

Try to repeat a task by using a standard sequence of operations

While carrying out a task, write down the sequence of operations you perform, in terms of physical actions such as keypad presses. Try to repeat the task a number of times by following this sequence exactly, without looking at or listening to the instructions. If the result is in any way different, then there is inconsistency.

2.3 When deploying more than one version of a device, ensure that the user interfaces are similar

Telecommunications services may be delivered through a number of different devices, which should use a similar presentation and interaction style. The layout of controls and keypads and the location and orientation of slots or dispensers for cards and coins should be the same on each version of the device.

Having completed a task on one type of telephone, the user should be able to complete the same task on a different type by carrying out a similar sequence of steps.

Rationale

People with cognitive or learning disabilities find it difficult when the presentation, interaction style or task flow varies. If there is no consistency between different telecommunications devices, users will have to repeatedly relearn the procedure.

Consistency is also vitally important for users who have difficulty perceiving the instructions and controls. Memorising a routine sequence of button presses to make and receive calls is the main strategy employed by blind telephone users. If the position of buttons is different from one device to another, their standard sequence is of no use to them.

Directions and Techniques

Adhere to standards

Achieve consistency with other telecommunications devices by using international or industry standards wherever possible. Standards exist for such things as symbols (e.g. ISO 7000 & 7001), colours and keypad layouts.

How you could check for this:

There are no specific test methods recommended for this guideline.

2.4 Ensure that videophones allow simultaneous text dialogue

Provide text functionality where possible, either as part of the videophone hardware or by allowing the connection of a separate dedicated device.

Rationale

Videophones that can handle text communication simultaneously enable an integrated method of exchanging information via a combination of sign-language, lip-reading and written text. The flexibility of this multimedia communication dramatically improves ease of use for some users.

Directions and Techniques

There are no specific techniques recommended for this guideline.

How you could check for this:

There are no specific test methods recommended for this guideline.

2.5 Do not require users to remember a fixed supplied PIN

If access to the device or service requires using a PIN, do not require users to remember one that has been supplied to them but not chosen by them.

Rationale

In Europe, over 25 million people have dyslexia to the extent that they cannot reliably remember and use a four digit PIN, unless they can choose their own number.

In addition, people with intellectual impairment may have a problem keeping the number secret, so a biometric identification method would be more suitable for them.

Directions and Techniques

Allow the user to select their own PIN

Either allow the user to make up a PIN when they register or, if one is supplied to them, allow them to change it at any time or at least the first time they use the device or service.

Provide an alternative access method

Consider providing an alternative access security mechanism such as biometric identification for users who find PIN numbers difficult to remember.

How you could check for this:

There are no specific test methods recommended for this guideline.

2.6 Provide for users with multiple impairments

Users with multiple impairments, such as those who are both visually and hearing impaired, should still be able to use the telephone. Features that are provided to accommodate users with different impairments should therefore be supplementary rather than mutually exclusive. That is, using one should not prevent the user from using others. If possible, visually impaired users should be provided with facilities that do not require good hearing. And hearing impaired users should be provided with facilities that do not require good vision or reading ability.

Rationale

Loss of vision, hearing and dexterity often occur together, particularly as the person gets older. For example, approximately 35% of people with a visual impairment also have a hearing impairment. A high proportion of people who are deaf also have low literacy. A 1993 NRB survey found that 80% of deaf adults in Ireland had the reading age of an 8-9 year old. This is due to the difficulties of learning through sign language, which has a different grammar and structure to spoken or written language, or by lip reading.

Directions and Techniques

Make modes of use complementary

Where alternative or enhanced input and output modes are provided, such as large text, graphical buttons, large buttons, audio output and tactile indicators, ensure that users can use them together. For example, instead of providing a choice between one user interface with large text and large buttons and another with spoken text and an spoken prompts, allow the user to choose any combination of these helpful features. The choice could be made by the user selecting from a number of displayed options. Alternatively, information required for the device to select options automatically could be encoded on a user's smart card or SIM card at their request.

How you could check for this:

There are no specific test methods recommended for this guideline.