john Gill technology header image

Design Features of Terminals to Improve Accessibility by Visually Impaired Persons

Dr. John Gill
August 2000

Universal design has been defined by the Center for Universal Design as "the design of different products and environments to be usable by all people, to the greatest extent possible, without the need for adaptation or specialised design. The intent of the universal design concept is to simplify life for everyone by making products, communications, and the built environment usable by more people at little or no extra cost. The universal design concept targets all people of all ages, sizes and abilities".

One might have thought that designers and service providers would be enthusiastic about implementing universal design principles if for no other reason than that it would increase the market for their products or services.

Unfortunately, in many countries, the impact of universal design has been modest up to now. Therefore it is important to influence the key players who include:

  • Politicians who can influence legislation
  • Authors of policy documents - these are often civil servants who may have no awareness of the potential impact of their work on the lives of disabled people
  • Standards bodies
  • System developers
  • Service providers

For example in the case of a cash dispenser, the company manufacturing the equipment sees their customer as the bank purchasing their equipment. Even though they may have incorporated universal design features in their range of terminals, it is to no avail if the bank is not interested in offering it to their customers. Within the bank it may be a technical department which is responsible for selecting equipment for the bank, but it will be the local branches who have direct contact with disabled customers and who may provide a modicum of training in the use of the cash dispenser. Unfortunately local branch staff are unlikely to be aware of the technological possibilities for improving the accessibility of the equipment.

The role of standardisation is significantly different in different parts of the world; in Europe it can be a powerful tool for implementing universal design.

Standards are crucial in the telecommunications industry where there is a rigorous, but if sometimes slow, process for developing standards. In the television industry, the process is somewhat different in that the technical standards are frequently determined by bodies made up of only industry representatives and there is no policy for involving consumers. The situation is different again in computer software where the commercially dominant players set the de facto standards with apparently no consultative process. This means that convergence is going to involve a clash of cultures as well as the more obvious problems of integrating three different groups of technology.

Standardisation is:

  • Time consuming
  • Low academic content
  • Often of little commercial benefit
  • A long term activity

So why is standardisation worth the effort involved? A couple of examples will illustrate how standardisation can be used to further universal design.

In the UK subtitling of television programmes for deaf viewers has been common for many years; this has been implemented using Teletext (ie text transmitted during the vertical blanking interval). However last November the UK started broadcasting digital terrestial television which gave a number of opportunities for improving accessibility. In particular it gave the possibility of changing from a crude mosaic typeface to one which is more legible on a television screen. However there had been no demand from deaf viewers for a change since they had not appreciated the possibilities arising from the change in technology.

Therefore a team was formed to develop a typeface for this application; the main criterion was legibility. Over 4000 fonts were examined but none proved suitable for the particular constraints of digital television.

The ScreenFont typeface was approved by the standards body, the Digital Television Group, for subtitling. Then the regulatory body, the Independent Television Commission, made it a mandatory requirement. This means, in effect, that it is illegal to use any other typeface for subtitling on digital terrestial television in the UK.

With this impetus, the tyepface is now being used for a number of other television applications - both the BBC and independent television will be using it for their text services. Now a number of other countries are planning to use the typeface - initially these are in western Europe but we had already included the extra characters used in French, German and the Scandanavian languages. We are in the process of adding characters for other languages, such as Czech, which use the Roman alphabet. However there have been requests for an equivalent typeface for non-Roman alphabets such as Greek and Arabic.

Another example of the role of standardisation concerns public access terminals such as cash dispensers, ticket selling machines and public telephones.

It is the user interface which causes most of the problems for visually impaired users. Some problems are caused by the environment such as sunlight on the screen - the effect can be reduced by a hood over the terminal. Another problem is the distance between the screen and the user's eyes which gives problems for users with bifocal spectacles.

Therefore it would be useful if the user could modify the user interface to suit their individual requirements. This could be selected by:

  • Button or menu
  • Stored in a central database
  • Stored on the user's card

This last option appears the most viable particularly with the increasing use of smart cards (alos known as chip cards) which can have significantly more memory than the conventional magnetic stripe cards. It would be possible to store user preferences for input, operation and output from the terminal.

Preferred input could include:

  • More time
  • Keyboard only
  • Touchscreen only
  • Speech recognition

"More time" could mean different things on different types of terminal. For instance:

  • On an ATM, more time before being timed out
  • On a public telephone, compose and send.
  • With an automatic gate, time for both guide dog and owner to get through

Preferred output could include:

  • Characters on visual display
  • size
  • colour foreground / background
  • font
  • Audio
  • feedback on key pressed

- speech prompts

  • speech output from screen
  • amplification
  • Icons
  • Braille display

The European standards organisation has developed a standard for how to code these requirements on a card; this standard will be mandatory in respect that it is not permitted to use any other method of coding on a card in Europe. Therefore the next task is for the user organisations to encourage service providers to implement this standard.

For the future, what is needed is a systematic approach to identifying opportunities for improving the accessibility of new systems, and then influencing the relevant organisations to incorporate the appropriate features.

Further information

Gill, J. M. & Carson, G. (1996) Smart cards: the coding of user interface requirements. London: RNIB.

Gill, J. M. (1998) Access prohibited? information for designers of public access terminals. [accessed 06/09/07].

Silver, J. H., Gill, J. M., Sharville, C., Slater, J. & Martin, M. (1998) A New Font for Digital Television Subtitles. [accessed 06/09/07].


John Gill Technology Limited Footer
John Gill Technology Limited Footer