Operating System Features Can Aid Accessibility

Mary Ziegler and Kathy Cahill

If you use a Macintosh or Windows computer with a reasonably up-to-date operating system, you have access to various built-in options that can make your computer easier to use. These options were developed for people with disabilities, but even if you don't face physical challenges, these features may help you reduce muscle or eye strain.

Macintosh OS 7.x & 8 offer the Easy Access and CloseView control panels. (Easy Access includes MouseKeys, SlowKeys, and StickyKeys.) Both control panels are on the Mac OS installation CD. If you don't have this CD, you can download Easy Access and CloseView from http://www.apple.com/disability/easyaccess.html

Two other Macintosh control panels - Keyboard and Speech - also get a mention in this article.

Windows 95 and NT offer many of the same features (though Windows offers some options not found on the Macintosh, and vice versa). You select the Windows features in the Accessibility Options control panel (which includes Keyboard, Sound, Display, and Mouse). If the options don't appear there, you can install them from your Windows CD. Click on Add/Remove Programs in the Control Panel, select Windows Setup, and click the check box next to Accessibility Options.

Keyboard and Mouse Options
Options for the keyboard and mouse are useful for people with fine motor control problems such as arthritis, cerebral palsy, multiple sclerosis, and Parkinson's disease. They are also favored by people with repetitive strain injuries, because they can reduce hand strain from stretching to reach keys or from using a mouse.

  StickyKeys (Macintosh and Windows).
Most applications have commands that require you to press two or three keys simultaneously. StickyKeys lets you issue a two- or three-key command by pressing one key at a time. Using a software keylatch, StickyKeys "locks" modifier keys (Control, Option, Command, Alt, or Shift) into place until another key is pressed.

Visual indicators and sounds alert you when StickyKeys is activated. On the Macintosh, an icon of an empty bucket appears in the upper right corner of the menu bar. When you press a modifier key, an arrow points into the bucket and a system sound plays.

In Windows, StickyKeys comes with an audio signal and a visual icon of three rectangular keys in the Task Bar. Each rectangle corresponds to a modifier key (Alt, Control, or Shift) and appears shaded when the key is locked.

  SlowKeys (Macintosh and Windows)
SlowKeys lets you adjust the amount of time you have to hold down a key before it registers a valid keystroke. For people with fine motor difficulties, this saves unwanted keystrokes from appearing on the screen.

  RepeatKeys (Windows) and Keyboard Control Panel (Macintosh)
These utilities let you adjust the Key Repeat Rate (how often a character repeats on the screen as you keep the key depressed). You can also set Delay Until Repeat, that is, how long you must depress the key after a character first appears before it appears again.
Note: In Windows, SlowKeys and RepeatKeys are packaged under the FilterKeys option, which in turn is found under the Keyboard option.

  MouseKeys (Macintosh and Windows)
MouseKeys lets you perform the functions of a pointing device with the numeric keypad of the keyboard. You can click, drag, and execute all the usual mouse movements by pressing designated keys on the keyboard.

Display Options
Features that let you alter the contrast or size of the screen display are useful for people with low vision conditions such as cataracts or glaucoma. Contrast settings can also be helpful for reducing eye strain.

  High Contrast (Windows) and CloseView (Macintosh)
High Contrast lets you activate a display mode to make it easy to distinguish between foreground and background. You can display white text on a black background or black text on white (this displays at a higher contrast than the default black on white).

CloseView magnifies screen contents up to 16 times the normal size. When activated, a black rectangle appears on the screen. The area inside the rectangle is magnified by the degree of magnification you have selected.

CloseView also has an option for displaying white text on a black background.

Sound Options
Windows 95 and NT have features that provide visual feedback in place of computer sounds. This can be helpful to the deaf and hearing impaired, who might otherwise miss critical audio feedback.

The sound-related access option built into the Macintosh serves a different audience. It lets the computer speak out loud, which can benefit users who are blind or have low vision.

  SoundSentry and ShowSounds (Windows)
SoundSentry sends a visible cue, such as a flashing title bar or active window, in the place of a system beep. ShowSounds instructs applications to provide visual feedback where possible, comparable to "close-captioned" TV.

  Talking Alerts (Macintosh)
Talking Alerts is an option in the Speech control panel. When turned on, the computer recites the system alerts that appear on the screen. If you click the OK button in an alert, the Talking Alert is cut off and you are returned to your application.

Questions?
If you need help configuring any of the access features described in this article, contact the ATIC Lab at x3-7808 or atic@mit.edu.