5.2. Overview of Assistive Technology Assistive technology is any tool that helps a person with a disability accomplish everyday tasks more easily. A specially designed "rocker" knife that makes it easier to cut food with the use of one hand is considered assistive technology . In computer terms, assistive technology helps people accomplish two fundamental tasks: input and output. These tools are not web specific; web usage is just one component of their overall utility.  | Don't overlook your own computer's capabilities. Windows XP and Mac OS X both include a lot of support for accessibility by default, and Sun Microsystems' Solaris 10 includes full accessibility support with voice capabilities, screen magnification, and onscreen keyboard functions. |
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5.2.1. Input Devices Assistive technology for input works to provide the same type of functionality that a keyboard and mouse provide. This means that for the most part, you as a web designer or developer simply need to ensure that what you create is operable by both keyboard and mouse. If you can do that, generally the assistive technology will take care of the rest (although some input considerations are discussed later in the chapter). Some example technologies are:
Alternative keyboards Alternative keyboards may provide a more functional key layout, be color-coded for cognitive disabilities, include larger keys, have a keyboard overlay or guide that aids in selection of the proper key, or be designed for one-handed use.
Virtual keyboards A virtual keyboard is one that is displayed on the screen to help people who may have difficulty typing but are able to use a mouse or some other pointing device effectively. Windows XP comes with a basic onscreen keyboard.
Voice recognition software Voice recognition software makes use of a computer's audio capabilities to detect a person's voice for two main purposes: transcribing voice to text and listening for operating commands. Voice command recognition is available at the operating system level (Mac OS X) as well as in voice-capable web browsers, such as the most recent versions of the Opera browser. Voice Recognition Approaches Voice recognition software has evolved significantly over the last decade. To activate a web link, you might simply say the link text. The voice recognition software then searches through the links it finds in the page, finds the correct one, and simulates a "click" on that link. So, what happens if you have multiple links with the same text? The software might highlight all of the links and overlay a number beside each, allowing you to speak the number of the link you'd like to follow. To fill in a form, you could speak the name of the field you wish to fill in, and the cursor will automatically be placed in the appropriate text box or form control. As you will see in Chapter 15, form controls must be labeled properly so that the voice recognition software knows exactly which form field should receive the focus. Some recognition packages enable users to overlay a numbered 3 x 3 grid on the computer screen by saying "mouse grid." The user then speaks the number of the grid portion of interest. The software overlays another numbered 3 x 3 grid within that space and the mouse cursor moves on the screen. This process continues until the grid is sufficiently small to put the mouse cursor where the user desires and the user issues the command to click or double-click. For example, to click on a radio button, you might have to say the following: "Mouse grid. Four. Three. Eight. Two. Five. Mouse click." |
Head and mouth wands These wands amount to a stick that is used to type on a regular or modified keyboard. These input devices are regularly used with a common operating system feature known as "sticky keys" that enables the user to press and release a modifier key, such as Ctrl, and then press another key, treating the sequence of keystrokes as if they happened in unison.
Face and eye tracking This technology generally uses software to follow the eyes or face of a person who has limited mobility and is unable to speak clearly enough to use voice recognition software. As users move their eyes, the mouse cursor follows. Various other actions may be used as a click or double-click. For an example, visit www.qualilife.com.
Switches Adaptive switches are highly specialized mechanisms that may simply serve as a single button mouse or may allow for greater flexibility with a set of foot switches, or a sip and puff mechanism. Again, these may be used in conjunction with specialized software to allow people to have full control of all the functions on their computer, including typing with automatic word-prediction. 5.2.2. Output Devices The normal sources of output for most everyday computer usage are the monitor and speakers. Captioning or transcripts can be of assistance, or users can turn to:
Screen readers Most screen readers are programs that interpret and interface with the actions that occur within the operating system and the applications that run on it. They provide extensive functionality through keystroke combinations and offer specific modes for specific functions. For example, Freedom Scientific's JAWS (www.freedomscientific.com) has normal reading, tables reading, and forms modes. They generally read some combination of the rendered HTML on the screen and do so based on source order. Other screen readers include: Window Eyes (GW Micro, www.gwmicro.com), HAL (Automated Living, www.automatedliving.com), and SuperNova (Dolphin Computer Access, www.dolphincomputeraccess.com).
Screen magnifiers Used by people with low vision, screen magnifier software simply provides an enlarged view of the onscreen text and graphics. Examples include ZoomText (Ai Squared Software, www.aisquared.com), SuperNova, and MAGic (Freedom Scientific).
Aural browsers Similar in function to screen readers, aural browsers are specialized for web use and provide less functionality than a full screen reader. Some examples are Home Page Reader (IBM, www-3.ibm.com/able/solution_offerings/hpr.html), which is a standalone program, and Connect Outloud (Freedom Scientific) and Browsealoud (Texthelp Systems, www.browsealoud.com), which are plug-ins for Internet Explorer.
Braille display These devices convert computer output to Braille, displaying the words via a set of movable pins that represent the current line of display. These devices are often used in conjunction with a screen reader. For example, the speech output from JAWS could be sent to a Braille display. |
