Computer input devices are external devices used to send task-specific information to computers. Such devices provide an interface between the user and the computer and are used to perform different functions. Common examples of input devices include a keyboard, mouse and scanner.
Computer input devices enable users to interact with computers through external hardware that can be attached or disconnected to the main computer unit. Computers often contain a variety of ports, such as USB ports, that allow easy connectivity between an input device and computer. Input devices are also replaceable, which serves to increase the lifespan of a computer in the event that one or more devices malfunction.
There are two classifications of input devices — direct and indirect. The former refers to devices that don't need to convert data before being read, while the latter refers to devices that need to convert the information into a readable data format before being processed. Examples of direct input devices include sales terminals, scanners and credit cards. Indirect input devices include devices like keyboards, joysticks and computer mice. In contrast to input devices, output devices are devices that convert machine-readable data into information that people can understand. These include devices such as monitors, printers and speakers.