238 Chapter 9 most particularly true for these products. The objectives for user interfaces are given below: · · · · The user interface should be intuitive to use, that is, most people should understand how to use it just by looking at it without additional instruction. The user interface should anticipate how a user will use the particular function in this device and be in the right location for that function. A user function should be enabled when (and only when) the user intends to use that function. The user interface should be simple and easy to see or perceive in some other way, for instance if the device can effectively use human speech it should be apparent how to talk to it and what it understands. The interface should use the best interface for the application it is used for both in terms of what people are used to for that function and in terms of the fit of the interface to that function--for instance if the device is to act like or provide control to a DVD player or television it might bring up buttons that emulate those used for these devices. If multiple functions for a device will conflict or make the user interface too complicated then the number of functions should be reduced (or hidden) so that the user does not become confused. A multiple function device that works well for users is likely to be a compromised device, and a full feature set professional device is more likely to be a single function device. · · · By following rules such as these, designers can make multiple function consumer devices that use digital storage easier for consumers to use and thus easier for them to adopt into their lives. Also, there will be a market for multiple purpose devices that work well but don't have the full feature set of more professional devices that focus on providing more advanced feature sets. Thus putting digital cameras in mobile phones does not destroy the market for more advanced single application digital cameras with zoom functions, advanced "f"-stop settings, and the other things that amateur or professional photographers require. Rather, such devices extend the applications for cameras for more professional users while the cameras in phones make it possible for anyone anywhere to take at least a recognizable photograph of something. www.newnespress.com