1. Although this section is reserved, manufacturers of telecommunications equipment and customer premises equipment are encouraged to provide redundancy such that input and output functions are available in more than one mode.
2. Alternate input and output modes should be selectable by the user.
3. Products should incorporate multiple modes for input and output functions so the user is able to select the desired mode.
a. Since there is no single interface design that accommodates all disabilities, accessibility is likely to be accomplished through various product designs which emphasize interface flexibility to maximize user configurability and multiple, alternative and redundant modalities of input and output.
b. Selectability is especially important where an accessibility feature for one group of individuals with disabilities may conflict with an accessibility feature for another. This potential problem could be solved by allowing the user to switch one of the features on and off. For example, a conflict may arise between captioning (provided for persons who are deaf or hard of hearing) and a large font size (provided for persons with low vision). The resulting caption would either be so large that it obscures the screen or need to be scrolled or displayed in segments for a very short period of time.
c. It may not be readily achievable to provide all input and output functions in a single product or to permit all functions to be selectable. For example, switching between such “modes” requires control mechanisms that themselves must be accessible. It may be more practical to have multiple modes running simultaneously. Whenever possible, it is preferable for the user to be able to turn on or off a particular mode.
4. Some experiments with smart cards are showing promise for enhancing accessibility. Instead of providing additional buttons or menu items to select appropriate input and output modes, basic user information can be stored on a smart card that triggers a custom configuration. For example, insertion of a particular card can cause a device to increase the font size on a display screen or activate speech output. Another might activate a feature to increase volume output, lengthen the response time between sequential operations, or allow two keys to be pressed sequentially instead of simultaneously. This technology, which depends on the issuance of a customized card to a particular individual, would allow redundancy and selectability without adding additional controls that would complicate the operation. As more and more functions are provided by software rather than hardware, this option may be more readily achievable.
5. The increasing use of plug-ins allows a product to be customized to the user's needs. Plug-ins function somewhat like peripheral devices to provide accessibility and there is no fundamental problem in using plug-ins to provide access, as long as the accessibility plug-ins are provided with the product. For example, at least one computer operating system comes packaged with accessibility enhancements that a user can install if wanted. In addition, modems are typically sold with bundled software that provides the customer premises equipment functionality. A compatible screen reader program, for example, could be bundled with it. At least one software company has developed a generalized set of accessibility tools designed to be bundled with a variety of software products to provide access. As yet, such developments are not fully mature; most products are still installed by providing on-screen visual prompts, not accompanied by meaningful sounds.
As a Guideline, 35 is unusual. Instead of specifying a performance characteristic, redundancy and selectability look at the overall design of the product’s user interface from an accessibility perspective. Redundancy and selectability are interrelated design principles rather than design features. The redundancy principle is that different users require different ways of controlling a product, perceiving its state, and controlling the format in which the transmitted content is being delivered. The selectability principle is that users must be able to set or adjust the way the product operates so that the redundancy is useful to them.
Redundancy and selectability are not defined in the Access Board Final Rule. We offer the following definitions: redundancy is the provision of a product’s input, control, and output functions through multiple modalities so as to maximize its ability to be used by people with different disabilities; selectability is the ability, comprehensible to the user, to choose among a product’s redundant modalities. A modality is a specific sensory or motor channel, such as hearing, vision, touch, speech, and arm/hand/finger movement.
In reviewing the products for this Report, we found several examples of redundancy and selectability. Where they occur, they are noted on that product’s data sheet. We have collected a few here to demonstrate the principles:
In some cases, adding redundancy and selectability without understanding the specific impact of features on user populations may still exclude a significant number of potential users. For example, IVR systems that require a touch-tone response may be hard for people with manipulation impairments to operate. Many newer IVR systems allow a caller to press a key or say the corresponding digit. This adds some new users – those with only manipulation impairments – but does not help the large number of individuals who have both speech and manipulation impairments.
Note that maximizing redundancy and selectability is not always the best design option. Increasing the number of modes or options among which users must choose may reduce the accessibility of the product for people with visual and/or cognitive impairments.
None.
None. This Guideline is concerned with the whole collection of features and their selection by users, not individual features.