SELECTION OF KEYBOARDS FOR ATIS DEVICES
Introduction: Selection of keyboards for ATIS devices refers to trade-offs and heuristics associated with fixed-function vs. variable-function keyboards. As discussed in Reference 1, examples of a fixed-function keyboard include cash register terminals and hand-held calculators; examples of a variable-function keyboard include keyboards for video games with different controls for different games, shifted keys of computer keyboards, and, in general, "soft" keys that can be changed via software control.
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Design Guidelines** (From Reference 1)
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Use fixed-function keyboards when:
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Use variable-function keyboards when:
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Advantages and Disadvantages of Fixed- and Variable-Function Keyboards (from Reference 1)
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Fixed-Function Keyboards |
Variable-Function Keyboards |
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Advantages |
Simplicity of operation Function is evident from key Minimal software support Logical key grouping |
Fewer keys Less visual search Less arm/hand movement Can be modified by software changes |
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Disadvantages |
Numerous functions require numerous keys Frequent visual search Frequent arm/hand movement Changes require hardware modification |
Increased function selection time Decreased clarity of key labeling Increased prompting and feedback requirements Increased training requirements |
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Supporting Rationale: The guidelines provided above reflect a review
and analysis of fixed- vs. variable-function keyboards reported in Reference
1. They reflect common usage of both fixed- and variable-function keyboards,
as well as general heuristics for their selection.
Special Design Considerations: It may be desirable to design ATIS devices so that they include both fixed- and variable-function keyboard elements. Functions that are common across ATIS tasks such as "Enter" or "Back" or "On/Off" might best be accomplished by using dedicated, fixed-function (or "hard") controls. Functions that involve selecting from among alternatives that vary from task to task (selection of: system functions, map scale, travel mode, etc.) might be best accomplished by using nondedicated, variable-function (or "soft") controls.
Also, while many devices can provide the driver with the ability to communicate with an ATIS (e.g., touch screens, speech controls, trackballs, push-buttons), keyboards are best for tasks that involve great amounts of text input, such as entering addresses for Routing and Navigation applications or entering preferences and services selection information for Motorist Services applications.
Cross References:
Key References:
1. Greenstein, J. S., & Arnaut, L. Y. (1987). Chapter 11.4: Human factors aspects of manual computer input devices. In G. Salvendy (Ed.), Handbook of human factors (pp. 1450-1489). New York: J. Wiley & Sons, Inc.
*Primarily expert judgement
** Expert judgement with supporting empirical data
***Empirical data with supporting expert judgement
****Primarily empirical data