Introducing the Buttons and Ports on a Computer

What is a Port?

In computer hardware, a port serves as an interface between the computer and other computers or peripheral devices. In the next lesson, we will look at peripheral devices. Computer ports have many uses, such as to connect a monitor, webcam, speakers, or other peripheral devices.


USB Ports. Photo Credit: Digital Trends

Take a look at the front and back of a computer case (if you have access to one) and count the number of buttons, ports, and slots you see. Now look at your monitor and count any you find there. You probably counted at least 10, and maybe a lot more.

Each computer is different, so the buttons, ports, and sockets will vary from computer to computer. However, there are certain ones you can expect to find on most desktop computers. Learning how to use these ports will help whenever you need to connect something to your computer, like a new printer, keyboard, or mouse.

Let’s look at the front of a computer case


Optical Disc Drive

Often called a CD-ROM or DVD-ROM drive, the Optical Disc Drive lets your computer read CDs and DVDs.

Power Button

The power button is used to power the computer on and off.

Audio In/Audio Out

Many computers include audio ports on the front of the computer case that allow you to easily connect speakers, microphones, and headsets without fumbling with the back of the computer.

USB (Universal Serial Bus) Port

Most desktop computers have several USB ports. These can be used to connect almost any type of device, including mice (plural of mouse), keyboards, printers, and digital cameras. They will often appear on the front and back of the computer.

Let’s look at the back of a computer case

The back of a computer case has connection ports that are made to fit specific devices. The placement will vary from computer to computer, and many companies have their own special connectors for specific devices. Some of the ports may be color coded to help you determine which port is used with a particular device.


Power Socket

This is where you’ll connect the power cord to the computer.

Audio In/Audio Out

Almost every computer has two or more audio ports where you can connect various devices, including speakers, microphones, and headsets.

Ethernet Port

This port looks a lot like the modem or telephone port, but it is slightly wider. You can use this port for networking and connecting to the Internet.

USB Ports

On most desktop computers, most of the USB ports are on the back of the computer case. Generally, you’ll want to connect your mouse and keyboard to these ports and keep the front USB ports free so they can be used for digital cameras and other devices.

Monitor Port

This is where you’ll connect your monitor cable. In the image above, the computer has both a DisplayPort and a VGA port. Other computers may have other types of monitor ports, such as DVI (digital visual interface) or HDMI (high-definition multimedia interface).

Serial Port

This port is less common on today’s computers. It was frequently used to connect peripherals like digital cameras, but it has been replaced by USB and other types of ports.


We sometimes use these ports for connecting the mouse and keyboard. Typically, the mouse port is green and the keyboard port is purple. On new computers, USB has replaced these ports.

Expansion Slots

These empty slots are where we add expansion cards to computers. For example, if your computer did not come with a video card, you could purchase one and install it here.

Parallel Port

This is an older port that is less common on new computers. Like the serial port, it has now been replaced by USB.

Other Types of Ports

There are many other types of ports, such as FireWire, Thunderbolt, and HDMI. If your computer has ports you don’t recognize, you should consult your manual for more information.

Ports on a Laptop Computer

Take a look at the image below. The image shows different ports on a laptop computer. Can you recognize some of the ports that look similar to those on the computer case above?


  1. Headphone (Audio Out)
  2. Microphone (Audio In)
  3. Security Lock Slot
  4. Optical Disk Drive
  5. Power
  6. Powered USB Port
  7. USB Ports
  8. HDMI (High-Definition Multimedia Interface for connecting high-definition video devices such as Plasma TVs.)
  9. VGA (Video Graphics Array for connecting video devices such as monitors and projectors.)
  10. Ethernet
  11. SD Card Reader 

Confused about anything that was mentioned in the lesson? Ask a question!


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