1193.41(a) Operable without vision
Provide at least one mode that does not require user vision.
1. Individuals who are blind or have low vision cannot
locate or identify controls, latches, or input slits by sight or operate
controls that require sight. Products should be manufactured to be usable
independently by these individuals. For example, individuals who cannot see must
use either touch or sound to locate and identify controls. If a product uses a
flat, smooth touch screen or touch membrane, the user without vision will not be
able to locate the controls without auditory or tactile cues.
2. Once the controls have been located, the user must be
able to identify the various functions of the controls. Having located and
identified the controls, individuals must be able to operate them.
3. Below are some examples of ways to make products
accessible to persons with visual disabilities:
- If buttons are used on a product, make them discrete
buttons which can be felt and located by touch. If a flat membrane is used
for a keyboard, provide a raised edge around the control areas or buttons to make it possible to locate the keys
by touch. Once an individual locates the different controls, he or she needs to
identify what the keys are. If there is a standard number pad arrangement,
putting a nib on the "5" key may be all that is necessary for identifying the numbers. On a QWERTY keyboard,
putting a tactile nib on the "F" and "J" keys allows touch typists to easily locate
their hands on the key.
- Provide distinct shapes for keys to indicate their function or make it easy to tell them apart. Provide Braille labels for keys and controls for those who read Braille to
determine the function and use of controls.
- Provide large raised letters for short labels on large objects. Where it is not possible to use raised large
letters, a voice mode selection could be incorporated that announces keys when pressed, but does not activate them. This would allow people to
turn on the voice mode long enough to explore and locate the item they are interested in, then release the voice mode and press the control. If it is an
adjustable control, voice confirmation of the status may also be important.
- Provide tactile indication on a plug which is not a self-orienting plug. Wireless connections, which eliminate the
need to orient or insert connectors, also solve the problem.
- Avoid buttons that are activated when touched to allow an individual to explore the controls to find the desired button. If touch-activated controls cannot be avoided (for example, on a touch screen), provide an alternate mode where a confirm button is used to confirm selections (for example, items are read when touched, and activated when the confirm button is pressed). All actions should be reversible, or require confirmation before executing non-reversible actions.
- Once controls have been located and users know what the functions are, they must be operable. Some types of controls, including mouse devices, track balls, dials without markings or stops, and push-button controls with only one state, where the position or setting is indicated only by a visual cue, will not be usable by persons who are blind or have low vision. Providing a rotational or linear stop and tactile or audio detents is a useful strategy. Another is to provide keyboard or push-button access to the functions. If the product has an audio system and microprocessor, use audio feedback of the setting. For simple products, tactile markings may be sufficient.
- Controls may also be shaped so that they
can easily be read by touch (e.g., a twist knob shaped like a pie wedge).
For keys which do not have any physical travel, some type of audio or tactile feedback should be provided so that the individual
knows when the key has been activated. A two-state key (on/off) should be physically
different in each position (e.g., a toggle switch or a push-in/pop-out
switch), so the person can tell what state the key is in by feeling it.
- If an optional voice mode is provided for operating a product, a simple
query" mode can also be provided, which allows an individual to find out the function and state of a switch without actually activating
it. In some cases, there may be design considerations which make the optimal
mode for a sighted person inaccessible to someone without vision (e.g., use of a
touch screen or mouse). In these cases, a primary strategy may be to provide a
closely linked parallel method for efficiently achieving the same results (e.g.,
keyboard access) if there is a keyboard, or "SpeedList" access for
Features that Address this Guideline
Controls grouped by function.
Keys identifiable by touch.
Nib on 5 key.
Speech recognition controls.
Speech recognition of outgoing spoken content.
Speech synthesis announcement of functions, status.
Tones indicating functions, status.
Variable or composable signal tones.