A coaxial cable is a type of network cable that carries electrical signals through a single central copper conductor, surrounded by insulation and shielding.
👉 The word "coaxial" means both conductors share the same axis. 🎯
• The inner conductor and outer shield are aligned on the same axis
• This design helps reduce signal interference
• Transmits electrical data signals ⚡
• Reduces electromagnetic interference (EMI) 📡
• Provides a stable signal over medium distances 📶
• Protects signal from external noise 🔇
Thicknet (10Base5)—long distance, difficult installation
Thinnet (10Base2)—flexible, short distance
BNC Connector—connects coaxial cable to devices
• Cable Television (DTH) 📺
• CCTV camera systems 🎥
• Broadband internet (old systems) 🌐
• Radio & antenna systems 📡
• Early LAN networks 🖧
• Better shielding than twisted pair
• Less affected by EMI
• More durable
• Suitable for analog signals
• Bulky and heavy
• Difficult to manage
• Lower speed than fiber
• Mostly obsolete in modern LANs
• Speed: Medium
• Distance: Medium
• Security: Moderate
• Cost: Medium
• Uses a single copper conductor
• Protected by metallic shielding
• Uses BNC connector
• Older Ethernet technology
• More resistant to noise than UTP
Coaxial = TV 📺 + CCTV 🎥 + Old Ethernet 🖧
If the interviewer asks:
👉 “What is a coaxial cable?”
Say confidently:
A coaxial cable is a shielded copper communication cable that transmits electrical signals with low interference.
A twisted pair cable is a network cable made of two insulated copper wires twisted together to transmit data signals.
The twisting reduces interference and improves communication quality.
• The wires are twisted to reduce electromagnetic interference (EMI) from external sources.
• Twisting also reduces crosstalk, which is interference between adjacent wire pairs.
• This design ensures that both wires are affected equally by noise, allowing the receiver to cancel it.
There are two main types of twisted pair cables used in networking.
• No metallic shielding
• Most common LAN cable 🏠
• Cheap and flexible 💰
• Affected by interference 📡
• Metallic shielding 🛡️
• Better EMI protection
• Used in industrial areas 🏭
• Expensive & grounding required
7. Key Differences Between UTP and STP
| Feature | UTP | STP |
| Shielding | No shielding | Metallic shielding |
| Cost | Low | High |
| EMI Protection | Moderate | Very high |
| Installation | Easy | Complex |
| Usage Area | Homes, offices | Industrial areas |
 |  |
• Twisted pair cables use copper wires.
• Interference is reduced mainly by twisting of wire pairs.
• UTP is the most commonly used LAN cable.
10. One-Line Memory Trick 🧠
UTP → Cheap, common, office cable
STP → Shielded, strong, industrial cable
If the interviewer asks:
👉 “Why do we use twisted pair cables?”
Answer confidently:
Twisted pair cable is a copper network cable where two wires are twisted together to reduce interference and provide reliable data transmission in LAN networks.
An optical fiber cable is a type of network cable that transmits data using light signals instead of electrical signals.
It is made of glass or plastic fibers and is used for very high-speed and long-distance communication.
• It provides very high data transmission speed.⚡
• It supports long-distance communication without signal loss. 📏
• It is immune to electromagnetic interference (EMI). 📡 ❌
• It offers better security compared to copper cables. 🔐
An optical fiber cable consists of three main layers:
• Core—The central part made of glass or plastic that carries light signals.
• Cladding—Surrounds the core and reflects light back into the core using total internal reflection.
• Outer Jacket – Protects the fiber from physical damage and environmental effects.
Electrical data → converted to light → travels inside fiber → converted back to electrical signal 🔄
• SC (Subscriber Connector)
• LC (Lucent Connector)
• ST (Straight Tip)
These connectors are used to terminate fiber cables to devices.
• Speed: Very High 🚀
• Distance: Very Long 📏
• Cost: High 💰
• Security: Very High 🔐
• Uses light instead of electricity
• Made of glass or plastic
• Best cable for high speed and long distance
• Immune to EMI
Optical Fiber = Speed of Light ⚡
If interviewer asks:
👉 “Why is optical fiber better than copper cable?”
Say confidently:
Optical fiber is better than copper cables because it offers higher speed, longer distance, better security, and is immune to electromagnetic interference.
Wireless networking is a method of connecting devices to a network without using physical cables.
In wireless networks, data is transmitted using radio waves instead of electrical signals or light.
🔐 No physical wiring required
🚀User mobility (move freely)
🔄 Easy installation
⚡Ideal for mobile devices
Data → converted into radio signals → transmitted through air → received → converted back into data
Wireless Router / Access Point—sends & receives signals
Wireless NIC—allows device connection
Antenna—transmits radio waves
Wireless Standards (Wi-Fi Standards)
Wireless networking mainly uses IEEE 802.11 standards, commonly known as Wi-Fi.
• No physical cables required
• Easy installation and expansion
• Supports mobility
• Convenient for modern devices
• Slower than wired networks
• Affected by interference
• Security risks if not configured properly
• Limited range
Wireless networks must be secured to prevent unauthorized access.
Common security methods:
• WPA / WPA2 / WPA3 encryption
• Strong passwords
• MAC address filtering
• Speed: Medium to High 🚀
• Distance: Limited 📏
• Cost: Moderate ⚡
• Security: Depends on configuration 🔐
One-Line Memory Trick 🧠
Wireless = No wires, more freedom 📶
If the interviewer asks:
👉 “What is wireless networking?”
Say confidently:
Wireless networking is a method of connecting devices to a network using radio waves instead of physical cables, allowing flexible and mobile communication.
Network topology refers to the physical or logical arrangement of devices and cables in a computer network.
It describes how devices are connected and how data flows between them.
• It affects network performance and speed
• It determines ease of installation and maintenance
• It impacts cost and scalability
• It helps in fault detection and troubleshooting
1️⃣ Star Topology
All devices connected to a central switch/hub
👉 Most common LAN topology
Pros: Easy management, good performance
Cons: Central device failure stops the network
2️⃣ Bus Topology
A single backbone cable connects all devices
Pros: Low cost
Cons: Cable failure stops the entire network
3️⃣ Ring Topology
Devices connected in a circular path
Pros: No collision
Cons: One break stops the network.
4️⃣ Mesh Topology
Every device is connected to every other device
Pros: Very reliable
Cons: Very expensive
5️⃣ Tree Topology
Hierarchical (Star + Bus combination)
Used in: Large organizations
6️⃣ Hybrid Topology
A combination of multiple topologies
Used in: Modern enterprise networks
• Star → Central device
• Bus → Single cable
• Ring → Circular path
• Mesh → Every device connected
• Tree → Hierarchy
• Hybrid → Mix of all
If the interviewer asks:
👉 “Which topology is best?”
Say confidently:
Star topology is the most commonly used because it is easy to manage, scalable, and provides good performance, while hybrid topology is used in large modern networks.
