External Features, Labels and Instructions
When a person has located a terminal, they need to know what type of machine it is, what it will do and how they can interact with it. The initial instructions are usually in the form of labels and signs applied to the surface of the terminal casing or as messages on the screen.
Labels should be placed where they can be easily read. If labels are positioned near the keyboard, it is important that the labels are not scuffed or worn away. If this is likely, the labels should be replaced periodically.
On outdoor terminals, braille has 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 2% of the visually impaired population so, although useful for some blind users, braille is not a total solution for visually impaired users.
Any instructions applied to the surface of the terminal should be written in simple and clear language. Type sizes as small as 10 point are not legible for many people. It is recommended that a type size of at least 16 point (4mm cap height) be used for labels.
It is useful to number instructions and associate the physical parts of the interface with the numbers. The numbers can also be shown on the visual display.
The following are key accessibility considerations:
- Labels are positioned for easy reading and legible for users with low vision;
- Numbered instructions are available, and simple, meaningful icons used.
More detailed information is provided in the guideline on labels and instructions