Three Types of Cables in Computer Networks

Cables in computer networks remain a vital component of modern network infrastructure, even with the rise of wireless technology. Wired connections continue to offer reliability and speed, which is evident in the use of Ethernet cables in home and office setups.

In this article, we will learn about the networking cables and understand different types of cables with their function and uses. We have explained all three types of cables: coaxial, fiber optic, and twisted pair cables, along with diagrams.

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What is a Cable in Networking?

A Network cable is a physical medium used to transmit data between devices such as computers, routers, switches, and servers. They are generally made up of conducting metals or glass.

A cable carries digital information in the form of electricity( in metal-based cables) or light (in glass-based cables). They are essential for connecting computer devices in both local and wide area networks.

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Types of Cables

There are three types of cables in computer networks: coaxial, twisted pair, and Fiber optic cables, each with unique characteristics and uses. Let's understand each of them in detail.

1. Coaxial Cable

A coaxial cable is a networking cable used for transmitting data, video, and voice signals. It transmits data in the form of electrical signals.

Coaxial cable is built with four main components:

1. Inner Conductor: A central wire, typically made of copper, which carries the electrical signal.

2. Dielectric Insulator: Surrounds the inner conductor, ensuring signal integrity and preventing interference.

3. Outer Conductor (Shield): Made of braided copper or metal foil, it protects the signal from external electromagnetic interference (EMI).

4. Outer Jacket: Provides physical protection and insulation for the cable.

Coaxial cables are mostly used in applications that require high-frequency signal transmission, like cable television, broadband internet, and radio.

The first coaxial cable was patented by Oliver Heavisine in 1880. They come in two primary impedance types: 50 Ohm for moderate power environments and 75 Ohm for residential installations and antenna connections.

2. Twisted Pair Cable

A twisted pair cable is a type of network cable made of pairs of insulated copper wires twisted together. The twisting helps reduce electromagnetic interference from external sources and crosstalk between adjacent pairs.

These cables are widely used in Ethernet networks and come in various categories (e.g., Cat5e, Cat6) that determine their speed and performance.

The structure of a twisted pair cable typically includes two main components:

1. Insulated Copper Wires: These are twisted together to minimize interference.

2. Shielding (Optional): Some cables include additional shielding to protect against electromagnetic interference.

Here is an image of twisted pair cable:

Twisted pair cables were invented by Alexander Graham Bell in 1881 and are mostly used in telephones, local area networks (LANs), and Ethernet connections.

There are two types of twisted pair cables:

● Unshielded Twisted Pair (UTP): UTP cables consist of multiple twisted pairs of copper wires, typically up to four pairs, each enclosed in a protective plastic jacket. The twisting helps reduce electromagnetic interference (EMI) and crosstalk between pairs

● Shielded Twisted Pair (STP): STP cables include an additional layer of shielding, such as aluminum foil or copper braid, which provides better protection against electromagnetic interference, making them suitable for high-speed networks and environments with significant EMI.

3. Fiber Optic Cables

A fiber optic cable is the fastest data transmission cable as it uses light signals instead of electrical signals to transfer data. Fiber optic cables were first developed in the 1970s. They transmit data as light signals through thin glass or plastic fibers, offering high-speed data transmission over long distances with minimal signal degradation.

The structure of a fiber optic cable typically includes three main components:

1. Core: The central part of the fiber where light travels, made from glass or plastic.

2. Cladding: Surrounds the core, reflecting light into the core to maintain signal integrity.

3. Outer Jacket: Provides physical protection to the fiber.

Fiber optic cables are mostly used in high-speed internet connections, telecommunications, and data centers due to their ability to support high bandwidths and long-distance transmissions.

There are two main types of fiber optic cables:

● Single-Mode Fiber: Used for long-distance transmissions, it has a smaller core diameter and supports a single light path.

● Multi-Mode Fiber: Suitable for shorter distances, it has a larger core diameter and supports multiple light paths, making it more versatile for local area networks.

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Categories of Cables

Network cables are categorized based on their function and speed. We have from Cat1 to Cat8 cables right now. Each category has a different purpose in networking, and the table below describes the specifications and uses of different categories of network cables.

How Different Cables Carry Data

1. Single-mode Fiber

Single-mode fiber uses a smaller core size (typically 9/125 microns) and a laser as the light source. It provides a single transmission path for light signals. A laser-based transmitter sends light at a single angle, hence the name single-mode.

Single-mode fiber cables are typically color-coded yellow. They are designed for long-distance communication, offering high bandwidth and low signal attenuation over extended distances.

Single-mode fiber is used for backbone networks and data centers requiring high-speed, long-distance connectivity. Here is the picture of sa ingle-mode fiber wherein one end is LC, and the other end is SC.

2. Multimode Fiber

Multimode fiber has a larger core size (commonly 50/125 or 62.5/125 microns) and uses either LED or laser light sources. It allows multiple light paths to propagate simultaneously. Cladding reflects the light into the core as it travels through the core.

Multimode fiber cables are typically color-coded orange. They are suitable for short to medium distances and provide lower-cost solutions compared to single-mode fiber.

Multimode fiber is commonly used in LAN environments, data centers, and campus networks where high-speed connectivity within a limited distance is required. Here is the picture of a multi-mode fiber wherein one end is LC, and the other end is SC.

3. Copper

Copper interfaces use electrical signals transmitted through copper wires or twisted-pair cables. Copper cabling includes various types such as Category 5e (Cat5e), Category 6 (Cat6), Category 6a (Cat6a), etc.

These cables consist of twisted pairs of copper wires enclosed in a protective jacket. Copper cabling is commonly used for Ethernet connections within shorter distances, typically up to 100 meters.

It is widely deployed in office networks, home networks, and other LAN environments. Here are the pictures of RJ-45 connectors and RJ-45 ports on a Cisco 3560CX switch.

Conclusion

In conclusion, network cables play a crucial role in modern communication systems, providing the infrastructure for data transmission across various environments. The primary types of network cables include coaxial, twisted pair, and fiber optic cables, each with distinct applications and advantages.

Twisted pair cables, categorized into different specifications like Cat5e, Cat6, Cat6a, Cat7, and Cat8, offer varying levels of bandwidth and speed, making them suitable for different networking needs.

Coaxial cables are commonly used in broadband and television connections, while fiber optic cables excel in high-speed, long-distance data transmission.