The ever-increasing presence of computers in everyone's lives has generated an awareness of the need to address computing requirements for those who have or may develop physical limitations. For these users, several different types of input and output methods can make their interactions with computers easier, more productive, and less frustrating.
Various input devices are available for users with motor disabilities (Harkin 34-75). A keyguard is a metal or plastic plate placed over the keyboard that allows users to rest their hands on the keyboard without accidentally pressing any keys. Small trackballs that the user controls with a thumb or one finger can be attached to a table, mounted to a wheelchair, or held in the user's hand. Another option for people with limited hand movement is a head-mounted pointer. To simulate the functions of a mouse button, a user works with a foot pedal, hand pad, or pneumatic instrument controlled by puffs of air.
Hearing-impaired users can instruct programs to display words instead of sounds. With many Windows operating systems, users also can set options to make programs easier to use. The Magnifier command, for example, enlarges text and other items in a window on the computer screen (Mindar 104-108). The location of the line on the computer screen that contains the mouse pointer is magnified at the top of the screen.
Visually impaired users can change Windows settings, such as increasing the size or changing the color of the text to make the words easier to read. Instead of using a monitor, blind users can work with voice output. That is, the computer reads the information that is displayed on the screen. According to Shelly and Cashman (Innovative Output Devices), another output alternative for visually impaired users is a Braille printer, which prints information on paper in Braille.
In today's world, it is difficult to imagine spending a single day not interacting with