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.
• Inner conductor and outer shield are aligned on the same axis
• This design helps reduce signal interference
A coaxial cable has 4 layers:
1️⃣ Inner Copper Conductor
• Carries the data signal
2️⃣ Dielectric Insulator
• Separates inner conductor and shield
• Prevents signal loss
3️⃣ Metallic Shield (Braid/Foil)
• Protects from EMI & noise
• Acts as ground
4️⃣ Outer Plastic Jacket
• Protects cable physically
• Transmits electrical data signals
• Reduces electromagnetic interference (EMI)
• Provides stable signal over medium distances
• Protects signal from external noise
1️⃣ Thick Coaxial Cable (Thicknet)
• Diameter is large
• Used in early Ethernet networks
• Supports longer distance
• Difficult to install
Example: 10Base5
• Smaller and flexible
• Easier to install
• Shorter distance
Example: 10Base2
• Bayonet Neill–Concelman
• Used to connect coaxial cable to devices
• Provides secure connection
Other connectors:
• F-type (Cable TV)
• N-type (Radio communication)
• 📺 Cable Television (DTH)
• 📷 CCTV camera systems
• 🌐 Broadband internet (older systems)
• 📡 Radio & antenna systems
• 🖥 Early LAN Ethernet 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
| Feature | Coaxial | Twisted Pair |
| Shielding | High | Low–Medium |
| Flexibility | Low | High |
| LAN usage today | Rare | Very common |
• Uses 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 interviewer asks:
👉 “What is a coaxial cable?”
Say confidently:
A coaxial cable is a communication cable that uses a single copper conductor surrounded by insulation and shielding to transmit electrical signals with reduced interference, commonly used in cable TV and CCTV systems.
A twisted pair cable is a type of network cable made of two insulated copper wires twisted together to transmit data signals.
• The twisting helps in reducing interference and improves the quality of communication.
• It is the most widely used cable in Local Area Networks (LANs).
• 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.
• UTP is a twisted pair cable that does not have any metallic shielding.
• It depends only on the twisting of wires to minimize interference.
• The twisting pattern reduces electromagnetic interference and signal loss.
• Since there is no shielding, UTP is lightweight and easy to handle.
• UTP cables are used in homes, offices, schools, and colleges.
• They are the standard cables for Ethernet LAN networks.
• UTP cables are low cost and affordable.
• They are easy to install, flexible, and lightweight.
• They support high-speed data transmission over short distances.
• UTP cables are more affected by electromagnetic interference.
• They are not suitable for environments with heavy electrical noise.
• UTP cables use the RJ45 connector.
• They follow T568A or T568B wiring standards.
• They mainly operate at the Physical Layer (Layer 1) of the OSI model.
• STP is a twisted pair cable that includes a metallic shield around the wire pairs.
• The shield provides extra protection against interference.
• The metallic shield blocks external electromagnetic noise.
• This ensures better signal quality compared to UTP.
• STP cables are used in industrial environments and data centers.
• They are suitable for places with heavy machinery or power cables.
• STP cables offer better protection from EMI and crosstalk.
• They provide more reliable and stable communication.
• STP cables are more expensive than UTP.
• They require proper grounding, which increases installation complexity.
• Grounding is mandatory for STP cables to work effectively.
• Improper grounding can reduce performance.
| 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 support short to medium distances.
• Performance depends on cable category (Cat5, Cat6, etc.).
• They are ideal for LAN environments.
• Twisted pair cables use copper wires.
• Interference is reduced mainly by twisting of wire pairs.
• UTP is the most commonly used LAN cable.
UTP → Cheap, common, office cable
STP → Shielded, strong, industrial cable
If interviewer asks:
👉 “Why do we use twisted pair cables?”
Answer confidently:
Twisted pair cables are used because twisting the wires reduces electromagnetic interference and crosstalk, making data transmission more reliable and cost-effective for 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.
Data is converted into light pulses using a laser or LED.
These light pulses travel through the core by total internal reflection.
At the receiving end, light signals are converted back into electrical data.
Definition
Single Mode Fiber allows only one light path to travel through the core.
It is designed for very long-distance and high-speed communication.
• Very small core diameter
• Uses laser light source
• Supports long distances
• Very high bandwidth
• Internet backbone
• ISP networks
• Long-distance WAN links
Definition
Multi Mode Fiber allows multiple light paths to travel through the core.
It is used for short-distance communication.
• Larger core diameter
• Uses LED light source
• Shorter distance
• Lower cost than SMF
• LAN networks
• Campus networks
• Data centers (short range)
• SC (Subscriber Connector)
• LC (Lucent Connector)
• ST (Straight Tip)
These connectors are used to terminate fiber cables to devices.
• Extremely high speed and bandwidth
• Supports very long distances
• No electromagnetic interference
• High security (hard to tap)
• Lightweight compared to copper
• High installation cost
• Fragile compared to copper cables
• Difficult to repair
• Requires skilled technicians
• Speed: Very High
• Distance: Very Long
• Cost: High
• Security: Very High
| Feature | Optical Fiber | Copper Cable |
| Signal type | Light | Electrical |
| Speed | Very high | Medium |
| EMI | No | Yes |
| Distance | Long | Short |
• 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.
