Alternate keyboards offer a variety of ways to provide input to a computer through various options in size, layout, and complexity.
Programmable keyboards can be programmed so letters, numbers, words, or phrases can be entered by pressing custom keys. They can be larger in size, allowing for a larger target area.
Miniature keyboards are designed with keys spaced close together to allow someone with a small range of motion to access all the keys.
Chording keyboards generally have a limited number of keys. Text is entered by pressing combinations of keys.
On-screen keyboards are software images of a standard or modified keyboard on the computer screen. Keys are selected by a mouse, touch screen, or other electronic pointing device.
Closed-circuit televisions (CCTVs) magnify the printed page with a special television camera and display the image enlarged on a monitor. CCTVs can be used to read print materials and to write notes, letters, and other handwritten documents with the aid of magnification. Potential users include those who require large text, and those who need high contrast text or specific text and background color combinations.
Optical Character Recognition and Scanners
Optical character recognition (OCR) software works with a scanner to convert
images from a printed page into a standard computer file. A scanner is a device
that converts an image from a printed page to a computer file. With optical character
recognition software, the resulting computer file can be edited. Pictures and
photographs do not require OCR software to be manipulated. People use these tools
to transfer a printed worksheet to the computer so it can be accessed by assistive
devices such as speech synthesizers, text enlargers, or Braille embossers. They
are also useful for changing text size, style, or layout.
Refreshable Braille Display
Refreshable Braille displays provide tactile output of information presented on the computer screen. Unlike conventional Braille, which is permanently embossed onto paper, refreshable Braille displays are mechanical in nature and lift small, rounded plastic or metal pins as needed to form Braille characters. They contain 20, 40, or 80 Braille cells. After the line is read, the user can "refresh" the display to read the next line. They can display commands, prompts, and electronic text in Braille, allow the user to get precise information about text attributes, screen formatting, and spelling on the computer display, and provide computer access to persons who are visually impaired, where speech output might not be practical or desired.
A screen reader is a software program that works in conjunction with a speech synthesizer to provide verbalization of everything on the screen including control buttons, menus, text, and punctuation. They can provide access to print materials and manuals after they have been scanned into a computer, provide auditory prompts, menus, and commands, provide confirmation of keystrokes without looking at the screen, and make a computer accessible to someone with limited or no vision.
TTY and TTY Modems
A Telecommunication Device for the Deaf (TTY or TDD) is a device with a keyboard that sends and receives typed messages over a telephone line. A TTY modem is a Weitbrecht/Baudot-compatible modem for a personal computer. A standard modem uses ASCII code to communicate over phone lines, while TTYs use Baudot code at a fixed baud rate of 45. A standard modem generally cannot communicate with a TTY, although some TTYs allow the user to select either Baudot or ASCII code at up to 300 baud. They are used to call other TTY users, call a relay system which will read your message to a standard phone user, and connect with automated services such as a bank.
Different types of voice recognition systems, also called speech recognition, are available. Voice recognition allows the user to speak to the computer instead of using a keyboard or mouse to input data or control computer functions. Voice recognition systems can be used to create text documents such as letters or email, to browse the Internet, and to navigate among applications and menus by voice. Voice recognition is commonly used to input text or data by voice, to navigate among files, applications, and menus, to execute standard commands by voice, and to control all functions of a computer hands-free.
Excerpted with permission from Computer and Web Resources for People with Disabilities. by the Alliance for Technology Access. Fully Revised Third Edition, 2001.