In computing, input/output, or I/O, refers to the communication between an information processing system (such as a computer), and the outside world ? possibly a human, or another information processing system. Inputs are the signals or data received by the system, and outputs are the signals or data sent from it. The term can also be used as part of an action; to "perform I/O" is to perform an input or output operation. I/O devices are used by a person (or other system) to communicate with a computer. For instance, keyboard and mouse are considered input devices of a computer, while monitor and printer are considered output devices of a computer. Devices for communication between computers, such as modems and network cards, typically serve for both input and output. Note that the designation of a device as either input or output depends on the perspective. Mouses and keyboards take as input physical movement that the human user outputs and