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Unit 6.2

Data Communication Media and Transmission

IT 231: IT and Application

Learning Objectives 🎯

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

  • ✅ Differentiate between guided (wired) and unguided (wireless) transmission media.
  • ✅ Identify common types of wired media, such as twisted-pair and fiber optic cable.
  • ✅ Define bandwidth and its importance in data transmission.

The Physical Path of Data

Transmission Media: The physical channel connecting a sender and receiver in a network.

Think of it as the "highway" that data travels on. 🛣️

Sender 💻 ➡️ Channel (Media) ➡️ Receiver 🖥️

Two Main Categories

1. Guided (Wired) Media

Signals are physically guided along a solid medium.

  • Twisted-Pair Cable
  • Coaxial Cable
  • Fiber Optic Cable

2. Unguided (Wireless) Media

Signals are broadcast through the air or space without a physical path.

  • Radio Waves (Wi-Fi, Bluetooth)
  • Microwaves (Satellite)

Guided Media: Twisted-Pair Cable

The Everyday Cable

  • Pairs of insulated copper wires twisted together.
  • Why twist? To reduce electronic interference (crosstalk). 🔍
  • Common Uses:
    • Ethernet (LAN) cables
    • Traditional telephone lines

This is the most common, cost-effective type of wired media for local networks.

Guided Media: Coaxial & Fiber Optic

Coaxial Cable

  • Single copper conductor at the center.
  • Insulated and shielded for better protection against interference.
  • Uses: Cable TV, older network setups.

⚡ Fiber Optic Cable

  • Transmits data as pulses of light!
  • Made of thin glass or plastic strands (fibers).
  • Uses: Internet backbone, high-speed business/home connections.

📊 Wired Media Comparison

Twisted-Pair

Speed: Good

Cost: Low

Interference: Susceptible

Coaxial

Speed: Better

Cost: Medium

Interference: More Resistant

Fiber Optic

Speed: Best 🚀

Cost: High

Interference: Immune

Key Takeaway: Fiber optic is the fastest and most reliable, but also the most expensive to install.

Unguided Media (Wireless)

Radio Waves 📡

Travel in all directions from the source (omnidirectional).

Easily pass through walls, making them great for indoor use.

Uses: Wi-Fi, Bluetooth, Cellular (4G/5G), FM Radio.

Microwaves

Travel in a straight line (unidirectional).

Requires a clear line-of-sight between transmitter and receiver.

Uses: Satellite communication, long-distance point-to-point links.

Key Concept: Bandwidth

Bandwidth: The maximum data transfer capacity of a network connection in a given amount of time.

Analogy: Think of it as the width of a highway.

  • A narrow, one-lane road = Low Bandwidth
  • A wide, multi-lane highway = High Bandwidth

Measured in bits per second (bps), e.g., Mbps, Gbps.

Practical Application in Nepal

Connecting a Nation

Nepal's internet backbone heavily relies on fiber optic cables connecting to India and China for international bandwidth.

In cities like Kathmandu, ISPs like WorldLink and Vianet use Fiber-to-the-Home (FTTH) for high-speed internet.

In remote, hilly regions, microwave and radio wave (wireless) links are crucial for providing connectivity where laying cables is difficult and expensive.

Summary & Key Takeaways 📝

  • Transmission media is the physical path for data, either guided (wired) or unguided (wireless).
  • Fiber optic cable offers the highest speed and capacity for wired connections and forms the internet's backbone.
  • Radio waves are the foundation for modern wireless technologies like Wi-Fi and 5G cellular networks.
  • Bandwidth measures the maximum data rate of a network connection—the "width of the pipe".

Thank You!

Any questions about transmission media or bandwidth?

Next Up: Unit 6, Chapter 3 - Network Topologies

Back to IT 231 Course Notes