Input refers to the data or commands that are sent to a computer. Input can take a variety of forms, including the commands a user enters from a keyboard and data that comes from another computer or device. Input can also be used as a verb when referring to the act of entering data to a computer.
An example of input can be found in TV settings. By pressing the “input” button on a TV remote control, the user is able to cycle through the available input devices (HDMI device, set top box, game console, etc.) that can transmit the input information to be displayed on the screen.
Input vs. output
The primary differentiator between input and output is the source of the information being transmitted. If it comes from a computer, the information is an output. If it comes from an external source, the information is an input.
A device that feeds data to a computer, such as a keyboard or mouse, is called an input device. An output device, on the other hand, is one that receives data from a computer, such as a display monitor or printer. Some devices operate as both input and output devices, including modems and network cards. Any device that writes data to and reads data from a computer’s CPU or memory is considered an input/output (I/O) device.