What is the difference between an input and output device?

Updated: 04/01/2018 by Computer Hope

Input and Output exampleAn input device sends information to a computer system for processing, and an output device reproduces or displays the results of that processing. Input devices only allow for input of data to a computer and output devices only receive the output of data from another device.

Most devices are only input devices or output devices, as they can only accept data input from a user or output data generated by a computer. However, some devices can accept input and display output, and they are referred to as I/O devices (input/output devices).

For example, as you can see in the top half of the image to the right, a keyboard sends electrical signals, which are received by the computer as input. Those signals are then interpreted by the computer and displayed, or output, on the monitor as text or images. In the lower half of the image, the computer sends, or outputs, data to a printer, which will print the data onto a piece of paper, also considered output.

Input devices

An input device can send data to another device, but it cannot receive data from another device. Examples of input devices include the following.

  • Keyboard and Mouse - Accepts input from a user and sends that data (input) to the computer. They cannot accept or reproduce information (output) from the computer.
  • Microphone - Receives sound generated by a user or other source (input) and sends that sound to a computer. It cannot receive and reproduce (output) sound sent by other devices.
  • Webcam - Receives images generated by whatever it is pointed at (input) and sends those images to a computer. It cannot receive and reproduce (output) images sent by other devices.

Tip: For additional information and examples, see our input device page.

Output devices

An output device can receive data from another device and generate output with that data, but it cannot send data to another device. Examples of output devices include the following.

  • Monitor - Receives data from a computer (output) and displays that information as text and images for users to view. It cannot accept data from a user or other source and send that data to another device.
  • Projector - Receives data from a computer (output) and displays, or projects, that information as text and images onto a surface, like a wall or a screen. It cannot accept data from a user or other source and send that data to another device.
  • Speakers - Receives sound data from a computer or other device (output) and plays the sounds for users to hear. It cannot accept sound generated by users and send that sound to another device.

Tip: For additional information and examples, see our output device page.

Input/Output devices

An input/output device can receive data from users or another device and also send data to another device. Examples of input/output devices include the following.

  • CD-RW drive and DVD-RW drive - Receives data from a computer (input), to copy onto a writable CD or DVD. Also, the drive sends data contained on a CD or DVD (output) to a computer.
  • USB flash drive - Receives, or saves, data from a computer or other device (input). Also, the drive sends data to a computer or another device (output).

Tip: For additional information and examples, see our input/output page.

Additional information