<P> In computing, an input device is a piece of computer hardware equipment used to provide data and control signals to an information processing system such as a computer or information appliance . Examples of input devices include keyboards, mouse, scanners, digital cameras and joysticks . Audio input devices may be used for purposes including speech recognition . Many companies are utilizing speech recognition to help assist users to use their device (s). </P> <P> Input devices can be categorized based on: </P> <Ul> <Li> modality of input (e.g. mechanical motion, audio, visual, etc .) </Li> <Li> whether the input is discrete (e.g. pressing of key) or continuous (e.g. a mouse's position, though digitized into a discrete quantity, is fast enough to be considered continuous) </Li> <Li> the number of degrees of freedom involved (e.g. two - dimensional traditional mice, or three - dimensional navigators designed for CAD applications) </Li> </Ul> <Li> modality of input (e.g. mechanical motion, audio, visual, etc .) </Li>

List of input and output devices of a computer