Cables For Computer Networking

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Just plug in that cable, and the network is up and running, right? Network cables work quietly, moving data from one location to another faster than we can blink. But what happens if everything goes wrong? Organizations rely so heavily on their networks that when the network fails, the business crumbles. That is why understanding how to repair physical networks is critical.

In this tutorial, we will be talking about the cables used in Computer Networking.

This tutorial will go over the cables used in computer networking.

Copper Twisted Pair

Most Ethernet networks and telephone communications use Category 5 cable for Ethernet, also known as CAT-5 cable. It has two distinguishing characteristics.

First and foremost, it has an unshielded twisted pair cable, also known as UTP cable. 
Second, it requires an RJ-45 connector on both ends.

Print on the outside of CAT-5 cables provides important information about the cable. For example, you can examine the outside of the cable to determine its type, speed, and any applicable standards.

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What’s inside a CAT-5 cable?

Opening up a CAT-5 cable reveals eight colored wires twisted into four pairs. One pair is brown, another is blue, yet another is green, and the last pair is orange. Each pair is made up of one plain wire and one striped wire.

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Why are the pairs twisted?

“Why are the wires inside Ethernet cables twisted?” many IT professionals and cabling experts wonder. The structure may appear to be a complete mystery until you investigate the mechanics at work. Keep reading to find out why the wires are twisted.

The problem with untwisted wires is that they produce magnetic fields that interfere with the signal carried by the wire. This means that electromagnetic interference and crosstalk are possible, both of which are detrimental to network data. When the wires are twisted, the magnetic field around them is effectively disrupted, reducing interference. The more twists the pairs have, the better.

Why Use Different Colored Pairs?

Not only are the twists in the wires significant, but so are the colors. Let us investigate further.

If you’ve ever looked inside an ethernet wire, you’ve probably noticed the various colors at work. These colors are used to indicate that they are using the same scheme on both ends. These couples typically follow the same pattern, with one wire in the pair being a solid or predominantly solid-colored wire and the other being primarily white with a colorful stripe.

The following is a typical example:

  • Blue and Blue/White
  • Brown and Brown/White
  • Green and Green/White
  • Orange and Orange White

Each color has a particular meaning, as does the color’s solidity.

Data is sent and received via orange and green wires.

The orange pair sends data, while the green pair receives data.

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The wire polarity is indicated by the color solidity.

When a wire is striped, it indicates that it is positive.  If the wire is solid, it is negative.

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Blue and brown wires are reserved for future bandwidth capacity.

Blue and brown wires are currently inactive, but will be in the future. The cable standards committee created CAT-5 with extra colored wires so that it could be used for higher bandwidths in the future.

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What’s the difference between bandwidth and speed on a network cable?

Bandwidth is a capacity; speed is a rate. Bandwidth tells you the maximum amount of data that your network can transmit. Speed tells you the rate at which the data can travel. The bandwidth for a CAT-5 cable is 10/100 Base-T. The speed of a CAT-5 cable changes depending on conditions.

What is Base-T?

Base-T refers to the different standards for Ethernet transmission rates. The 10 Base-T standard transfers data at 10 megabits per second (Mbps). The 100 Base-T standard transfers data at 100 Mbps. The 1000 Base-T standard transfers data at a massive 1000 Mbps.

There are two types of twisted-pair cable: unshielded twisted pair (UTP) and shielded twisted pair (STP). The Type we have discussed so far is UTP. The sections that follow go into greater detail about UTP and STP cable.

UTP Cable

An insulating material is wrapped around each of the eight individual copper wires in the UTP cable. Furthermore, the wires in each pair are twisted around one another.

To limit signal degradation caused by electromagnetic interference (EMI) and radio frequency interference (RFI), UTP cable relies solely on the cancellation effect produced by the twisted wire pairs (RFI). The number of twists in the wire pairs varies to reduce crosstalk between the pairs in UTP cable. UTP cable must adhere to strict specifications governing the number of twists or braids permitted per meter (3.28 feet) of cable.

A Registered Jack 45 (RJ-45) connector is commonly used to connect UTP cable. The RJ-45 connector is an eight-wire connector that is commonly used to connect computers to a local-area network (LAN), particularly Ethernets.

Although UTP was once thought to be slower than other types of cable in terms of data transmission, this is no longer the case. In fact, UTP is currently the fastest copper-based medium. The following features of UTP cable are summarized:

  • Speed and throughput—10 to 1000 Mbps
  • Average cost per node—Least expensive
  • Media and connector size—Small
  • Maximum cable length—100 m (short)

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Q: Aren’t there newer, faster cable standards like CAT-5e and CAT-6?

CAT-5e and CAT-6 cables are newer standards for cables. We cover CAT-5 because it’s the base framework for the higher cable standards. CAT-5e and CAT-6 have bandwidths of 10/100/1000 Base-T.

Shielded Twisted-Pair Cable

Shielded twisted-pair (STP) cable combines shielding, cancellation, and wire twisting techniques. Each wire pair is wrapped in metallic foil (see the following figure). The four pairs of wires are then wrapped in a metallic braid or foil, which is usually 150-ohm cable. STP, as specified for use in Ethernet network installations, reduces electrical noise both within and outside the cable (pair-to-pair coupling, or crosstalk) (EMI and RFI). STP is typically installed with a STP data connector, which was designed specifically for the STP cable. STP cabling can also use the same RJ connectors as UTP.

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Although STP is more effective at preventing interference than UTP, it is more expensive and difficult to install. Furthermore, both ends of the metallic shielding must be grounded. If the shield is not properly grounded, it acts as an antenna, picking up unwanted signals. STP is rarely used in Ethernet networks due to its high cost and difficulty in termination. STP is most commonly used in Europe.

The following summarizes the features of STP cable:

  • Speed and throughput—10 to 100 Mbps
  • Average cost per node—Moderately expensive
  • Media and connector size—Medium to large
  • Maximum cable length—100 m (short)

Keep the following points in mind when comparing UTP and STP:

  • The speed of both types of cable is usually adequate for short distances.
  • These are the least expensive data communication media. UTP is less costly than STP.
  • Because UTP is already used in most buildings, many transmission standards have been adapted to use it in order to avoid costly rewiring with an alternative cable type.

Coaxial Cable

Coaxial cables, like CAT-5 cables, are used to create a network. Coaxial cabling is a type of network cabling that is commonly found in older Ethernet networks as well as electrically noisy industrial environments. The term “coax” refers to the cable’s two-conductor construction, in which the conductors run concentrically along the cable’s axis. For local area network (LAN) installations within buildings, twisted-pair cabling has largely replaced coaxial cabling, as has fiber-optic cabling for high-speed network backbones. 

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There are two significant differences between twisted-pair cable and coaxial cable.

1 Instead of four twisted pairs, the cable has one large copper wire.
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2 The cables use different sorts of connectors and terminators.
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How Does Coaxial Cable Work?

Coaxial cabling is typically made up of a solid copper core for signal transmission, followed by layers of inner insulation, aluminum foil, a copper braided mesh, and outer protective insulation. A solid conductor is more conductive than a stranded conductor, but it is less flexible and more difficult to install. The insulation is typically PVC (polyvinyl chloride) or a nonstick coating, with aluminum foil and copper mesh shielding the inner copper core. The mesh also serves as a grounding point for the cable, completing the circuit.

Coaxial cabling is frequently used in heavy industrial environments where motors and generators generate a significant amount of electromagnetic interference (EMI) and where more expensive fiber-optic cabling is unnecessary due to the slow data rates required. In IBM mainframe and minicomputer environments, coaxial cabling is also commonly used. When connecting two 3270 terminals to one IBM mainframe system, a device known as a splitter can be used to split a single coaxial cable into two. At either end of the connection, a splitter is used to send signals from both terminals over a single coaxial cable. Coax multiplexers can connect up to eight terminals to a single controller.

Fiber-Optic Cables

Fiber-optic cables use light rather than electrons to transmit network data. The network signal is carried by light as it bounces through the cable’s interior. The light travels through the fiber-optic cable’s transparent core. This core is made of transparent glass or plastic, allowing light to easily pass through it. Cladding is the layer just outside of the core. Cladding functions similarly to a mirror, reflecting light so that it bounces along the core rather than escaping.

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The cable’s exterior is coated with polymer, and Kevlar threads running between the core and the coating add strength and protection.

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A fiber-optic cable’s ends, like CAT-5 and coaxial cables, have connectors. There are numerous connector types that can be used.

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In simple words, Networking cables are pieces of networking hardware that connect one network device to another or two or more computers to share devices such as printers or scanners. These cables basically transmit network signal using different mechanisms. In the next tutorial we will talk about network signal.

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