Learning Objectives

By the end of this chapter, you will be able to:

  • Define an I/O port and its function.
  • Identify common I/O ports like USB and HDMI.
  • Define the system bus and its role in the computer.

Connecting Peripherals: I/O Ports

An I/O (Input/Output) port is a physical connector on a computer that allows you to connect external peripheral devices. These ports are the interface between the computer and the outside world.

Common I/O Ports

  • USB (Universal Serial Bus): The most common type of port, used for connecting a wide variety of devices, including keyboards, mice, printers, and external drives.
  • HDMI (High-Definition Multimedia Interface): Used for transmitting high-definition video and audio from a computer to a monitor or television.
  • Audio Jacks: Used for connecting speakers, headphones, and microphones.
  • Ethernet Port: Used for connecting to a wired network.

The System Bus: The Computer’s Highway

The system bus (also called the motherboard bus) is the communication pathway that connects all of the major components of a computer, including the CPU, RAM, and I/O ports. It is like a highway system that allows data to travel between all the different parts of the computer.

The system bus is composed of three main parts:

  1. Data Bus: Carries the actual data being transferred.
  2. Address Bus: Carries the information about where the data is supposed to go (i.e., the memory address).
  3. Control Bus: Carries control signals from the CPU to coordinate the activities of all the other components.

Summary

I/O ports are the physical sockets that allow us to connect external devices to a computer, with USB being the most common standard. Internally, all of the computer’s components, including the CPU, RAM, and I/O ports, are connected and communicate with each other via the system bus, which acts as the main data highway of the motherboard.

Key Takeaways

  • I/O ports are physical connectors for peripheral devices.
  • USB is the most common and versatile I/O port.
  • The system bus is the communication pathway that connects all the major components of a computer.

Discussion Questions

  1. Look at the back of a desktop computer or the side of a laptop. What I/O ports do you see?
  2. Why is it called the “Universal” Serial Bus (USB)?
  3. Using the highway analogy, what would happen if the system bus was too slow for the CPU?