<Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> In computing, input / output or I / O (or, informally, io or IO) is 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 . </P> <P> I / O devices are the pieces of hardware used by a human (or other system) to communicate with a computer . For instance, a keyboard or computer mouse is an input device for a computer, while monitors and printers are output devices . Devices for communication between computers, such as modems and network cards, typically perform both input and output operations . </P> <P> The designation of a device as either input or output depends on perspective . Mouse and keyboards take physical movements that the human user outputs and convert them into input signals that a computer can understand; the output from these devices is the computer's input . Similarly, printers and monitors take signals that a computer outputs as input, and they convert these signals into a representation that human users can understand . From the human user's perspective, the process of reading or seeing these representations is receiving input; this type of interaction between computers and humans is studied in the field of human--computer interaction . </P>

Input/output devices that enable users to communicate with computers are called