The standards address technical functions and performance requirements, and vary from one technology to another. In some cases they ensure compatibility with adaptive equipment often used to improve access for the disabled, such as braille displays or screen readers. In other cases they recommend internal systems changes or conventions.
In many instances, systems can be made more accessible by making the information available to more than one sense or ability. Having information only in an audio format, for example, makes that information inaccessible to people with hearing loss. Providing the information in written and audio format thus increases accessibility to that information.
The standards seek practical benefits for people with disabilities. For operating and applications software, the standards deal largely with alternative access for people with impaired vision. One section of the standards, for example, deals with alternative pointing and navigation devices other than the familiar mouse. A large part of the standards for telecommunications systems deal with hearing loss and recommend ways of becoming compatible with hearing aids, assistive listening devices, and TTY terminals.
For Web sites and services, the standards borrow from the Web Accessibility Initiative of the World Wide Web Consortium (W3C). Some of the recommendations include making provisions for assistive devices such as screen readers or refreshable braille displays. In other cases, the recommendations are similar to good Web design principles, such as using alternative text tags with images. These recommendations often make sense for any Web users who turn off images to speed page loading, or disable time-consuming animation displays, not just those with disabilities. Alternative text-only pages can also help downsize Web pages for use on wireless or hand-held displays.
The W3C’s Web Accessibility Initiative offers a series of simple tips to improve accessibility of Web sites; see http://www.w3.org/WAI/References/QuickTi...
- Images & animations. Use the ALT attribute to describe the function of each visual.
- Image maps. Use client-side MAP and text for hot-spots.
- Multimedia. Provide captioning and transcripts of audio, and descriptions of video.
- Hypertext links. Use text that makes sense when read out of context. For example, avoid "click here."
- Page organization. Use headings, lists, and consistent structure. Use Cascading Style Sheets for layout and style where possible.
- Graphs & charts. Summarize or use the LONGDESC attribute.
- Scripts, applets, & plug-ins. Provide alternative content in case active features are inaccessible or unsupported.
- Frames. Use NOFRAMES and meaningful titles.
- Tables. Make line by line reading sensible. Summarize.
