Because of physical disabilities, many people can not use a standard keyboard or mouse. This limits their participation in many educational and work activities, their access to information, and their inclusion in society as a whole. This is ironic because computers can greatly improve the lives of many people with disabilities.
Alternate Input Devices
A number of devices have been developed to meet this need. These products, known as alternate input systems, allow computers to be controlled in a variety of ways. Joysticks, switches, video game controllers, touch screens, and non-standard keyboards are some of the devices which can be used to meet the needs of the disabled user. Morse code, scan mode, expanded keyboard and Darci code are some of the input methods which are used with these devices.
The term "transparent access" was coined by the Trace Center to describe how well an alternate input system works with a computer. If a system provides 100% transparent access, the alternate input device is "transparent" to the computer and it works with all hardware and software.
Types of Alternate Input
Alternate input systems fall into two general categories, hardware based systems and software based system. There are advantages and disadvantages associated with both approaches. Software systems gain their functionality by running special software on the computer. This reduces their cost but, because they're software based, they can't provide 100% transparent access. This means that they may not work well with all computers and separate systems must be developed for each operating system. Hardware based systems can be designed to work with all software and can provide 100% transparent access. But these systems must duplicate much of the hardware found in the computer. This makes them expensive to develop and manufacture.
What Features Should an Alternate Input System Have
An alternate input system should fill the needs of the user. Because each user has very different needs (and desires), the system must be flexible. Listed below are some of the more important features which are found in high quality alternate input systems. The more of these capabilities a system has, the more certain it is that it will meet the needs of the user. There are many other features which enhance the usefulness of alternate input systems and they should be evaluated before a system is selected.
Every system should:
- Provide 100% transparent access - This means that it will work with all of the applications on the user's computer.
- Work with both Apple and IBM compatible computers - People often need to use different types of computers in school and in the workplace.
- Work with all current operating systems - This means DOS, Windows 3.1, Windows 95, OS/2, and System 7 (Apple Macintosh).
- Provide complete keyboard and mouse input capabilities - Some applications can not be used unless all inputs are provided, including keypad keys.
- Allow the keyboard and the mouse to be used at the same time as the input device - This allows the computer to be shared; a feature which is especially valuable in a teaching environment.
- Provide an interface to several types of input devices (joystick, switches, etc.) - People's needs change and their ability to control a particular type of input can change.
- Provide different modes of operation - People's needs change over time. Someone who uses scan mode might decide that they could be more productive if they used Morse code. The device should be able to be adapted to meet those needs.
- Allow customization - Every feature on the device which can be changed (especially timing) should be adjustable and those adjustments should be accessible to the user.
- Provide audio and visual feedback - The user's accuracy and speed are enhanced by these capabilities.