Assistive Technology for Computers
Assistive technology, also called accessibility aids, are added to computers
by people who use them to make computers more accessible. Some common aids
include:
Screen magnifiers help people with low vision. These utilities
are like a magnifying glass. People using them are able to control what
area of the computer screen they want enlarged, and can move that focus
to view different areas of the screen. They are also known as screen enlargers
or large print programs.
Screen readers are for people who are blind. These aids make
on-screen information available as synthesized speech or a refreshable
Braille display. They can only translate text based information. Graphics
can be translated if there is alternative text describing the visual images.
They are also known as blind access utilities or screen reviewers.
On-screen keyboards are used by people who are unable to use
a standard keyboard. An on-screen keyboard lets people select keys using
a pointing method such as pointing devices, switches, or Morse-code input
systems.
Keyboard enhancement utilities are used by people who have trouble
typing and controlling a mouse. They allow the user to perform complicated
key sequences serially (e.g. Control-C), control the mouse pointer and
buttons from the keyboard, and set the key repeat and acceptance rates.
These ehancements are built into the base platform and are known as AccessX
on Solaris/CDE, AccessPac on Microsoft Windows, and EasyAccess on the Mac.
Speech recognition programs are primarily used by people with
mobility impairments. These utilities enable people to control computers
with their voice instead of a mouse or keyboard. They are also known speech
recognition programs.
Alternative input devices allow individuals to control their
computers through means other than a standard keyboard or pointing device.
Examples include smaller or larger keyboards, eye-gaze pointing devices,
and sip-and-puff systems controlled by breathing.
The following is a larger list af assistive technologies broken down
by the disability type who benefits from them.
TABLE 1. Assistive
Technologies for Physical Disabilities and RSI
| Assistive Technology |
Function Provided |
Alternate
Pointing Device |
Gives users with limited or no arm and hand fine motor control
the ability to control mouse movements and functions. Examples include
foot operated mice, head-mounted pointing devices and eye-tracking systems. |
| Screen Keyboard |
On-screen keyboard which provides the keys and functions
of a physical keyboard. On-screen keyboards are typically used in conjunction
with alternate pointing devices. |
| Predictive Dictionary |
Predictive dictionaries speed typing by predicting words
as the user types them, and offering htose words in a list for the user
to choose. |
| Speech Recognition |
Allows the user with limited or no arm and hand fine motor
control to input text and/or control the user interface via speech. |
TABLE 2. Keyboard Enhancements
| Feature |
Function Provided |
| StickyKeys |
Provides looking or latching of modifier keys (e.g., Shift,
Control) so that they can be sued without simultaneously pressing the keys.
This allows single finger operation of multiple key combinations. |
| MouseKeys |
An alternative to the mouse which provides keyboard control
of cursor movement and mouse button functions. |
| RepeatKeys |
Delays the onset of key repeat, allowing users with limited
coordination time to release keys. |
| SlowKeys |
Requires a key to be held down for a set period before keypress
acceptance. This prevents users with limited coordination from accidentally
pressing keys. |
| BounceKeys |
Requires a delay between keystrokes before accepting the
next keypress so users with tremors can prevent the system from accepting
inadvertent keypresses. |
| ToggleKeys |
Indicates locking key state with a tone when pressed, e.g.,
Caps Lock. |
TABLE 3. Assistive
Technologies for Low Vision and Blind Users
| Assistive Technology |
Function Provided |
| Screen Reader Software |
Allows users to navigate through windows, menus, and controls
while receiving text and limited graphics information through speech output
or braille display. |
| Braille Display |
Provides line by line braille display of on-screen text
using a series of pins to form braille symbols that are constantly updated
as the user navigates through the interface. |
| Text to Speech |
Translates electronic text into speech via a speech synthesizer. |
| Screen Magnification |
Provides magnification of a portion or all of a screen,
including graphics and windows as well as text. Allows users to track position
of the input focus. |
TABLE 4. Assistive
Technologies for Hearing Disabilities
|
Assistive Technology
|
Function Provided
|
| Telecommunications Device for the Deaf (TDD) |
Provides a means for users to communicate over telephone
lines using text terminals. |
| Closed Captioning |
Provides text translation of spoken material on video media.
Important computer applications include distance learning, CD-ROM, video
teleconferencing, and other forms of interactive video. |
| ShowSounds |
Proposed standard would provide visual translation of sound
information. Non-speech audio such as system beeps would be presented via
screen flashing or similar methods. Video and still images would be described
through closed captions or related technologies. This capability would
be provided by the system infrastructure. |
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