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Public Access Terminals

John Gill

 

To fully participate in society, individuals will need to be able to use self-service terminals.  Many government departments may have plans for using public access terminals for providing information, collecting taxes, granting licences, administering regulations, paying grants and benefits, collecting and analysing statistics, and procuring goods and services.  Some of these services may also be available through direct contact with a human, but there may be an additional charge for using this facility.

To make significant progress in the accessibility of public access terminals by disabled and older people will require terminal manufacturers and service providers to adopt a “design for all” policy.  In addition there will need to be agreement to standardise a number of aspects of the user interface of such terminals.

 

THE SCIENTIFIC BASIS

Occasionally recommendations for standards for the human-computer interface are based on rigorous scientific research with a cross-section of potential users.  Unfortunately this is expensive and therefore is often omitted or done with a very small sample of potential users.  This is not necessarily a serious problem in that often the recommendations could be described as "common sense", but it can lead to standards which are later proved to be fallacious.

A common method for deriving a standard is to quote the contents of another standard without verifying whether the detailed recommendations are appropriate.  Sometimes recommendations have been what is thought best within certain technological limitations, but the recommendations have not been altered when the technology changed.

For instance the typeface for subtitling on analogue television was limited to a mosaic typeface.  However with digital television the limitations are fewer, but programs made for analogue television must be able to be broadcast on digital television without reauthoring the subtitles.  In this case, the existing recommendations for typefaces for people with low vision were examined, but were found to have obvious flaws. 

Other problems can occur with the adoption of new assistive technology.  For instance scooters used by physically disabled persons are significantly different in height from conventional wheelchairs, which means that recommendations for the height of keypads and screens on public terminals may no longer be valid.

In other areas guidelines have been constrained by external factors.  For instance most people with low vision would benefit from a high level of illumination in the immediate vicinity of an outdoor cash dispenser.  However the bank staff responsible for security do not want such illumination since it makes life easier for muggers; the customer withdrawing money would be looking from a bright area to a much darker area and might not see someone waiting to rob them.  Therefore the recommendations on illumination levels have had to be compromise between what is beneficial for low vision persons and what is acceptable to the bank.  However well-lit areas, not just at the cash dispenser, would make the environment safer for everybody.


GENERAL DESIGN  CONSIDERATIONS

For many disabled and older users, the most important aspect is consistency in the user interface of public terminals; this is particularly important for visually, intellectually and cognitively impaired users.  A prime example of this is the lack of a single standard relating to the layout of numeric keypads.  With public terminals, the user may only use it occasionally and has probably been provided with minimal training in the use of the terminal.  What is “logical” to the average user may be different from what is “logical” to the designer, so it is essential to test any new user interface with a cross-section of potential users (including disabled and older people).

To select a preferred interface such as audio instructions or large characters on the screen, the user could simply press a button or otherwise select from a menu on the screen; this is likely to increase the time taken to undertake a transaction if there are more than a few options.  Another possibility is to store the user’s preferences on a central computer and implement them as soon as the PIN (personal identification number) has been entered.

For card-operated terminals, it is possible to store the information on the user’s card (the coding of user requirements is specified in the European standard EN1332-4), and this is in many ways more desirable than storing private information about a user on a central database.  With a magnetic stripe card there is very limited spare capacity for storing this information (but this method has been used for storing the user’s preference for displayed language), but a smart card (containing an electronic chip) has fewer restrictions on storage capacity so appears to be ideal for this purpose.
Many disabled users would like to be able to select and store their preferred interface whenever they use their card at a public access terminal.  It is essential that information is stored on a card only with the consent of the user.

 

Locate Terminal

For a blind person, it can be difficult to find the terminal if they are not very familiar with the environment.  One possibility is to use a contactless smart card, carried by the blind person, to trigger an audible signal from the terminal at a distance of a few metres.

 

 

Instructions

Instructions should be written in simple clear language and presented at eye height in at least 16 point bold characters, preferably in white or yellow on a dark matt background.  It is important that the instructions are not worn away with use of the terminal (or they should be replaced periodically).  It is often useful to number the instructions and then associate by number with the physical parts of the interface (eg card reader) as well as showing the number on the visual display.  Ideally the user should be able to choose the language; frequently this is only viable if the instructions are displayed on the screen, and it would be preferable if the user’s card stored their preferred language and that the terminal automatically switches to this as soon as the card is inserted.

Public access terminals can incorporate audio prompts in the form of ‘beeps’, to indicate an action. It is recommended that new equipment should provide a more sophisticated solution of using audio leadthrough in the form of a verbal set of instructions.  Audio leadthrough can assist people with visual or cognitive impairments (and first time users). 

Sentences should be concise and simple in structure, and only natural vocabulary should be used.  Informative messages which advise the user of the progress of the transaction and inform the user when or how to perform a step in the transaction, should be clear and to the point, and provide confirmation of task completion.  Message content should be chosen very carefully since a message that might be acceptable to the users for the first few times they hear it may become unacceptable when they hear it for the hundredth time. Many users with impaired hearing, who can only hear lower frequencies, can more easily hear a male voice than a female one.

If audio output is used to provide private information to the user, then it should be through a telephone handset located at the terminal or through a headset connected through a standard mini jack to the terminal; however, it is essential that the position of the jack socket is standardised.  If a handset is provided, inductive coupling and amplification should also be incorporated.

Braille instructions on outdoor terminals have limited value in cold weather since tactual sensitivity is dramatically reduced with decreasing temperature.  The estimated number of braille readers in Europe is less than 200,000 so although useful for some blind users, braille is not a total solution for visually impaired users.

 

Card Insertion

For a blind person, there is a problem in selecting the right card from their wallet; unfortunately there is no standard method for tactually marking cards to indicate the issuer or their use.  This problem will be exacerbated with the increasing use of cards which feel the same. 

For the naïve user, it is often far from obvious where to insert the card.  A flashing light around the card entry slot has been found beneficial.  For those with hand tremor, it is useful if the entrance to the card reader acts as a funnel to guide the card in correctly.

Blind persons, and many older persons, have problems in inserting the card in the correct orientation; this is a particular problem on cards which are not embossed.  However there is a draft European standard for an orientation notch (prEN1332-2) in the card:

For many wheelchair users, such as those with arthritis, it is not just a problem of reaching the card reader, but still having any useful grip as the arm is raised above the horizontal.

The lowest height of any operable part of the user interface should not be less than 0.7 metres. Ideally the terminal, or user controls, should be adjustable in height; although this is done on some drive-in cash dispensers, it does significantly increase the cost of the terminal.  However the problems of accessing the card reader are greatly alleviated if contactless smart cards are used; for this type of application they typically have an operating range of 10 to 20 cm.

 

Reading the Screen

People who wear bifocals find it difficult to read the screen of most public access terminals, since neither lens is in focus at the distance between their eyes and the screen.  In addition many people leave their spectacles in the car or do not wear them in public.  So the number of people who have problems in reading the screen is much more than those considered “blind” or “low vision”, who constitute about 1.5% of the population.

People with low vision should not be prevented from getting their faces close to the screen.  However it is possible to increase the size of the characters on the screen for individual customers who require this facility.  This can be done by selecting this option from a menu or preferably by storing this information on the customer’s card.  With touchscreen systems, it could be arranged that holding one’s finger in the top left corner for at least two seconds indicates that one would like double size characters on the screen.

Total colour blindness is rare (less than 0.0025% of the population) but problems with discriminating red and green are common (over 6% of the male population).

Moving text on a screen can be very difficult to read for someone with even a mild sight impairment, so it should be avoided whenever possible.

Digitally stored speech can give very good audio quality, but it is effectively limited to pre-stored messages.  Full vocabulary synthetic speech is often difficult to understand for the naïve user, particularly if they have a hearing impairment.  Non-confidential information can be output on a loudspeaker, but the volume should be a function of the current ambient noise level; this is less of a problem with handsets or headphones.  If there is an inductive loop for hearing aid users, there should be a clear visual indication that this is the case (NB not all hearing aids have facilities for loop connection).

One technological possibility would be for a disabled user to have a hand control unit with an infra-red link to the terminal.  This would require all terminals to use the same interface protocol, and care would be needed to ensure confidentiality of sensitive information. 

Sunlight can degrade the viewability of the display for all users. The site should be one where direct or reflected sunlight or other glare is prevented from striking the visual display.  The display should be viewable from an eye level of a person sitting in a wheelchair or a scooter; this results in problems in specifying absolute heights since the dimensions of scooters varies considerably.  One solution, albeit expensive, is to have the user interface on the terminal be adjustable in height; this is particularly important if the terminal is likely to be used by children as well as adults (as in a post office).

The conflicting requirements from tall pedestrian users and short wheelchair users can lead to a significant group of users having parallax problems when lining up the function keys with the displayed option.  Lines on the user-interface leading from the key to the surface of the display can alleviate this problem.

Displayed text should use simple, large, bold fonts in upper and lower case characters.  Displayed messages should be simple in sentence structure, use natural language, and any graphical symbols (such as icons) should be accompanied by text.

 

Keyboard

Personal identification numbers (PINs) are a particular problem for many dyslexic and intellectually impaired people. Both these groups would find it advantageous to have the option of using a biometric method for identification (eg fingerprint).

With biometric methods of identification it is essential that users have a choice between the biometric method and some other method (eg PIN); the reason being that for many biometric systems there is some group of disabled people who cannot use it (eg fingerprint identification requires the user to have fingers); the exception is facial recognition.
The user’s PIN should not be displayed, printed or broadcast by any means. However it would be useful to have both an audible feedback and a visual one (eg an X on the screen) to show that a digit has been input. Many people with even slight memory problems find it difficult to remember and input their PIN quickly, so it would be helpful to allow a generous amount of time before they are timed out.

Information, which is sensitive and private to the cardholder, should not be visible to any other person; screen filters improve privacy but often at the expense of visual quality.  However the user may wish to display information with large character size, but they should be made aware of the privacy problem.

Standard layout of keypads is essential for visually disabled people and highly desirable for other users.  To help blind persons, there should be a single raised dot on the number five key.  However this does not solve the problem of there being two common layouts for the numeric keys (ie the telephone and the calculator layouts); it is recommended that the telephone layout is used exclusively on public access terminals.

All keys or buttons should be tactually discernible; keys should be raised or recessed by a minimum of 2 mm.  The edges of the keys should be at least 2.5 mm apart.  Function keys should be clearly separated from the numeric keys.


Visual markings on the keys should be characters of at least 4 mm high and should have good contrast with the colour of the key (eg white characters on matt black keys). Where text keys are colour coded, they should be coloured as follows:

Key meaning

Colour

Enter or proceed

Green

Clear or correct

Yellow

Cancel

Red

Colour should not be the only distinguishing feature between keys, since red/green colour blindness is not uncommon; if possible, the keys should have different shapes and be marked with symbols.

Ideally keys should be internally illuminated when the terminal is waiting for input from that keypad.  There should be some form of feedback on key input (eg a beep and/or tactual indication).  Tactile feedback can be provided by a gradual increase in the force, followed by a sharp decrease in the force required to actuate the key, and a subsequent increase in force beyond this point for cushioning.

Many older people and those with a cognitive impairment do not like to be rushed or to think that they are likely to be “timed out” by the machine, so it is necessary to allow for such people to use the terminal at their own pace; this requirement could be stored on the user’s card.

Speech input for commands is an option in some situations.  If this is adopted then the user should have the choice of keyboard or speech input.  It is likely that speech input would be preferred by people without hands and those with intellectual impairments, but the keyboard is easier for those with a speech impediment.

 

Touchscreens

To help older people and those with hand tremors, key fields should be as large as possible and separated by a ‘dead area’.  There should be high contrast between touch areas, text and background colour.  Avoid using a pretty picture as background - it is a menace to anyone with poor vision or someone reading the screen under difficult conditions (eg in bright sunlight).

For blind users, one possibility is to arrange that holding one’s finger in a specified corner of the screen for at least two seconds initiates speech output (NB this must be a different corner than the one used to request large characters on the display), or tapping twice in the corner.  Another method would be to store this requirement on the user’s card.

Touch screens can either be triggered by insertion or withdrawal of the fingertip.  With the latter system, it is technically possible for the user to pass their fingertip over the screen and get speech output describing the active area they are touching at the time.  Then the system is only triggered by withdrawing the fingertip from over an active area.

 

Money Retrieval

Cash, receipt, or any other document issued from the terminal for withdrawal by the user should protrude at least 3 cm beyond the slot surround.

For someone with poor manual dexterity, such as with arthritis, taking a card from a terminal and then taking the money may be difficult to do in the allowed time.  Increasing the time for everybody, increases the security risk.  However it would be possible to let users decide if they want more time than the standard time permitted, and store this requirement on their card.

Security at cash dispensers is a major concern for many older people, and is often given as a reason for not using such terminals.  Therefore anything which improves the user’s perception of safety is to be welcomed.

 

Receipts

To aid visually impaired users, receipts should have a minimum font size of 12 point with a sans serif typeface with upper and lower case text, but 16 point would be preferable if space permits.  It is important that the print has good contrast on opaque paper with a minimum of background pattern.  A common complaint is poor print quality on receipts which is often a result of the printer ribbon not being replaced regularly.

 

Card Retrieval

Many people with arthritis have difficulty in gripping and pulling the card from the reader, particularly when the arm is extended above the horizontal.  The card should protrude at least 2 cm from the slot surround.  Therefore it is recommended that the force necessary for the user to retrieve the card from the terminal should be not any greater than that needed to stop the card from falling out of the reader.

 

Training

All too often it is assumed that users will learn to operate a self-service terminal just by reading the brief instructions attached to the terminal.  However the instructions must be comprehensible to all users and not just the system's designer.  For instance the instruction "Enter your PIN" is not meaningful to many older persons; an alternative might be "Please key in your personal number now".

Service provides have proved very reluctant to provide users with training in the use of their terminals.  This has resulted in many older persons not using services because they could not operate the terminal.

 

CONCLUSION

The increasing use of terminals intended for use by the general public makes it essential that the needs of disabled and older people are taken into account when the systems are being designed.  Many features which are essential for disabled people, are advantageous for all users.

 

FURTHER INFORMATION

 

COST 219bis
http://www.stakes.fi/cost219
This site is concerned with access to telecommunications by disabled and elderly people.

Include
http://www.stakes.fi/include
This is the main European web site concerned with designing information and communication technology systems so that they are accessible to everybody including disabled and elderly people.  This site contains a wealth of information including demographics of disability in Europe, relevant standards as well as legislative aspects.

Public Access Terminals
http://www.eyecue.co.uk/pats
Describes features of public access terminals which would make them easier to use by disabled people.

Telephones
http://www.tiresias.org/phoneability/telephones
Describes 44 design features in telephones which would be of benefit to people with disabilities.

Trace
http://tracecenter.org/docs/consumer_product_guidelines/consumer.htm
Guidelines for the design of consumer products to increase their accessibility to people with disabilties or who are aging.

Screenphones
http://www.rnib.org.uk/wedo/research/sru/phones.htm
Guidelines for the design of screen and web phones to be accessible by visually disabled persons.

ScreenFont
http://www.eyecue.co.uk/tiresias
This site gives details of a font specially designed for legibility on televisions for applications such as subtitling.

Web Accessibility
http://www.w3.org/tr/wai-webcontent/
These guidelines explain how to make web content accessible to people with disabilities. The guidelines are intended for all web content developers (page authors and site designers) and for developers of authoring tools. The primary goal of these guidelines is to promote accessibility.

 

 



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