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Unit 3.8

Understanding I/O Ports and Buses

IT 231: IT and Application

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: What is an I/O Port?

An I/O (Input/Output) port is a physical connector on a computer that allows you to connect external peripheral devices.

Think of them as the doors and windows of your computer, letting information in and out.

Common I/O Ports 🔌

USB (Universal Serial Bus)

  • The most common and versatile port.
  • Connects keyboards, mice, printers, external drives, and more.
  • Provides both data transfer and power.

HDMI (High-Definition Multimedia Interface)

  • Transmits high-definition video and audio.
  • Connects your computer to monitors, TVs, and projectors.
  • A single cable for both picture and sound.

More Common I/O Ports 🎧🌐

Audio Jacks (3.5mm)

  • Used for connecting headphones, speakers, and microphones.
  • Often color-coded:
    • Green: Audio Out (speakers/headphones)
    • Pink: Mic In

Ethernet Port (RJ-45)

  • For a wired network connection.
  • Provides a faster and more stable connection than Wi-Fi.
  • Essential for gaming and large file transfers.

🔍 Activity: Port Spotting in Nepal

Look around you!

Examine your laptop, a desktop in the lab, or even a smart TV. How many of these ports can you find?

  • USB (Type-A, Type-C?)
  • HDMI
  • Ethernet
  • Audio Jack

Context: In many offices and homes in Nepal, the Ethernet port is crucial for a stable internet connection, especially when power cuts or "load shedding" affect Wi-Fi router stability.

From Ports to the Core ⚡

So, these ports let us connect devices to the computer.

But how do the ports, the CPU, and the RAM all talk to each other inside the machine?

Answer: The System Bus

The System Bus: The Computer's Highway 🛣️

The system bus is the communication pathway that connects all the major components of a computer, including the CPU, RAM, and I/O ports.

It is the data superhighway built into the motherboard, allowing data to travel between all the different parts of the computer.

Anatomy of the System Bus

The system bus is actually made of three separate buses working together:

1. Data Bus

Carries the actual data being transferred.

2. Address Bus

Carries the information about where the data is supposed to go (the memory address).

3. Control Bus

Carries control signals from the CPU to coordinate all activities.

System Bus Analogy: A Postal Service 📮

Data Bus is the...

Package

(The actual information)

Address Bus is the...

Delivery Address

(Where the package is going)

Control Bus is the...

Postman's Instructions

('Deliver', 'Sign Here', etc.)

Discussion: The Bottleneck Effect

Using the highway analogy, what would happen if the system bus was too slow for the CPU?

It creates a bottleneck.

A fast CPU with a slow bus is like a Ferrari stuck in Kathmandu's traffic. The overall system performance is limited by its slowest component.

Summary & Key Takeaways 📊

  • I/O ports are the physical sockets that allow us to connect external devices to a computer.
  • USB is the most common and versatile I/O port, handling both data and power for many devices.
  • The System Bus is the internal highway on the motherboard connecting the CPU, RAM, and I/O ports.
  • The bus is composed of a Data Bus, an Address Bus, and a Control Bus.

Thank You!

Next Up: Chapter 9 - Understanding Storage Devices

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