🌐 CN-4: Networking Devices & Cables (Part 1)

1️⃣ Introduction

Before diving into advanced devices, let’s understand the building blocks of networks — the cables that carry signals and the simple devices that connect them.

2️⃣ Cables in Networking

🔌 Unshielded Twisted Pair (UTP) Cable

• Commonly used in LAN connections.

• Made of twisted copper wires.

• Example: Ethernet cables (Cat5, Cat6).

• Range: ~100 meters.

• Cost: Cheap and easy to install.

• ⚡ Example: Your home Wi-Fi router connected to a PC often uses UTP cables.

📡 Coaxial Cable

• Copper core with insulation and shielding.

• More resistant to noise than UTP.

• Used in old Ethernet (10Base2, 10Base5) and cable TV connections.

• ⚡ Example: The black cable your TV set-top box uses.

💡 Fiber Optic Cable

• Transmits data using light signals.

• Extremely high speed and long distance.

• Very expensive and fragile.

• ⚡ Example: Undersea internet cables connecting continents.

✨ What does 100Base-T mean?

• 100 → Speed (100 Mbps)

• Base → Baseband signaling

• T → Twisted pair cable
  👉 So 100Base-T = Ethernet over twisted pair cable at 100 Mbps.

3️⃣ Networking Devices

🔁 Repeater

• First, what is attenuation?
  Attenuation = weakening of signal as it travels through a cable.

• A repeater boosts the weak signal and forwards it.

• Number of Ports: 2

• Forwarding: Yes (it only forwards, no intelligence).

• Filtering: ❌ No (cannot check addresses).

• Collision Domain: Does not break it (same collision domain).

• ⚡ Example: Imagine shouting across a field. A friend in the middle repeats your message loudly so the other side can hear. That’s a repeater.

• Diagram idea: PC → [Repeater] → PC

  

📶 Hub

• A hub is like a multi-port repeater.

• Sends incoming signal to all connected devices.

• Number of Ports: 4–24

• Forwarding: Yes (broadcasts to all).

• Filtering: ❌ No (no intelligence).

• Collision Domain: All devices share the same collision domain.

• Special Feature: Indicates connection errors via blinking lights.

• ⚡ Example: Think of a hub as a loudspeaker in a classroom — when one student speaks, everyone hears it (even if it’s not meant for them).

• Diagram idea: Multiple PCs → [Hub] → signals go to all

4️⃣ Summary Table

5️⃣ Closing Note

This blog covered cables (UTP, Coaxial, Fiber) and the simplest devices (Repeater & Hub).
In CN-5, we’ll continue with Bridges, Switches, and Routers — smarter devices that bring intelligence to networks.

✅ Stay tuned for CN #5: Exploring the OSI Model!
🧵 Follow the entire CN series to master networking step-by-step.