What is both an input and output device?

Technology has improved significantly over the last two decades so understanding what is both an input and output device can be confusing. A lot of modern technology has elements of both types of devices whereas in the past different technology would serve different purposes.

Input and output devices are components that send data to and receive data from your device’s processor. Performing input and output operations forms a core part of their primary function. Network cards are a perfect example of an input/output, or I/O, device, as they have to constantly send and receive data to keep you connected to a work. 

Before diving into the components that are both input and output devices, let’s explore what input and output devices are. 

What are input, output, and I/O devices?

Network card - input / output device
A network card

Let’s take a closer look at the differences between input, output, and I/O hardware. It’ll help us to understand why different components operate as both inputs and outputs. 

Input Devices

An input device is a piece of hardware that connects to your computer and sends information into the central processing unit. They typically record human actions in some manner. 

A game controller is an input device that records the buttons you press and the direction you move on the joystick. It then forwards this data onto the CPU which moves your in-game character. The touchpad on your laptop is also an input device but it tracks your finger movements and then provides the processor with updates so the on-screen cursor can be moved accordingly. 

Output Devices

An output device is a piece of hardware that connects to your computer and functions by receiving information sent by the CPU. Output devices respond to instructions from your device’s processor rather than capturing human behavior like input devices.

A plotter is an output device that receives instructions in the form of designs or drawings that need to be printed. It then outputs these as hard copies on paper. Your speakers are output devices that receive data in the form of audio files and output it as sound. 

Input and Output devices

Input and output devices can function as both input and output devices. Rather than being limited to just sending or receiving information from the central processing unit, they can do both. 

Your network card is an I/O device that continually talks back and forth with your computer and the external network. Similarly, your sound card provides input, and out of audio when using multimedia applications on your device. Both of these typically sit on your motherboard.

What is both an input and output device?

Now that we have covered what defines an input and output device, let’s explore what components are both an input and an output device. 

It’s important to remember that depending on your perspective most devices could be perceived as an input or an output. Most modern devices speak back and forth with the processor in some way. 

However, to simplify things I take the approach that we should define a device based on its primary task. While a mouse may at times speak back and forth with the CPU its primary job is to track and send movement data. Similarly, a printer may send information to the CPU regarding toner levels, but its main function is to output hard copies of your documents. 

So our list of devices that are both input and output devices will contain components that operate as both as part of their core functionality. Devices that are both inputs and outputs include:

  1. Network cards
  2. Touchscreens – the display is the output the touch is the input
  3. Sound/audio cards
  4. Modems
  5. Headsets – they use both speakers and a microphone
  6. Fax machines – they use a scanner and a printer
  7. Radios – they both send and receive radio signals off the same antenna 
  8. 3.5mm jacks
  9. CD and DVD drives 
  10. USB ports

Plenty of devices have input and output capabilities, for example, a multi-function printer could be included on the list. However, a multi-function printer is basically a composition of other devices like a scanner, printer, and fax all in one. So the list above is just for devices that function as I/O devices as part of their primary function. 


Devices that are both Inputs and outputs can send and receive information from the central processing unit. They perform input and output operations as a part of their core functionality and usually form crucial parts of your computer. I/O devices are often used to communicate between computers and external software operating inside your computer – think network cards, modems, and sound cards.

Remember that most components perform some sort of input and output operation. But for simplicity, we should classify devices by what their primary function is.