The Basics – What is a Network Cable?
Network cable set-ups can range from simple, localised data transfer – such as connecting two devices in the same room or building via a standard Ethernet cable such as the RJ45 – to complex interconnections spanning enormous distances.
In recent years, wireless technology has superseded the dominance of network cable connections to an extent, but they still play a vital role in facilitating seamless, secure data transfer and communications.
Types of network cable
Network cables take a number of forms depending on the particular function they're designed to carry out. Some are interchangeable; others can only be applied to specific tasks and devices. It's important to understand which type of cable is best suited to your requirements before making a purchase.
Twisted Pair
A twisted pair network cable consists of pairs of independently insulated wires that are twisted together to prevent electromagnetic interference and 'crosstalk' from other devices. One wire acts as the primary signal carrier, while the other is a grounded wire that blocks interference.
The two most common forms of twisted pair cable are Shielded Twisted Pair (STP) and Unshielded Twisted Pair (UTP).
UTP is generally the less expensive of the two cable types, and is found in many Ethernet networks and telephone systems. They generally contain between eight and fifty individual copper wires, grouped into twisted pairs encased in a colour-coded protective coating. In addition to being more affordable than STP, they are also lighter and easier to install, although their lack of shielding can make them more vulnerable to interference.
STP works in much the same way as UTP, but adds an extra layer of protection by shielding each twisted pair with a metallic substance - usually a wire mesh or sheet metal. All of the pairs are then wrapped together in another metallic protector. The function of this is to prevent electromagnetic interference. As a result they are considered more secure than UTP, and are often used in Token Ring networks.
At a glance
Strengths: Inexpensive, widely available, suitable for analog and digital data transmission
Weaknesses: Easily damaged, vulnerable to signal interference over long distances.
Use for: Ethernet connections, short-range connections, general telephone & network connections.
Buy Twisted Pair network cables from industry leading manufacturers
Fibre Optic Cable
Fibre optic cables consist of a glass or plastic fibre core - typically only slightly wider than a human hair - surrounded by several layers of protective material. While the copper wiring contained in traditional network cabling transfers data through electricity, fibre optic cables use light. This allows them to transmit data over long distances at higher speeds and with less loss. Immunity to the distorting effects of electrical noises and ground currents makes them ideal for areas that are exposed to high amounts of interference.
Fibre optic cables are a more expensive option compared to standard copper wiring, but offer clear advantages in enhanced speed, bandwidth and reliability that has made them a popular choice for use in large business infrastructure. They are also increasingly accessible for domestic and smaller business use, with most internet providers now offering affordable fibre optic broadband packages.
One limitation of fibre optic cables is that they can only propagate light in one direction. For instances where bidirectional communication is necessary, two concurrent cables must be laid in order to transmit the information.
At a glance
Strengths: Fast, reliable, high band width, secure, scalable.
Weaknesses: Expensive, easily damaged, unidirectional.
Use for: Long distance connections, high bandwidth data transfer requirements.
Buy Fibre Optic cables from industry leading manufacturers
Coaxial Cable
Coaxial cables are shielded copper cables that provide an interference-free transmission path for high-frequency electrical signals. A central conducting wire - usually solid or braided copper - is surrounded by a dielectric insulating layer and a metal foil or braided copper mesh, and coated in a protective plastic jacket. This layered construction prevents interference and keeps the signal enclosed, and lends the name ‘coaxial’, which refers to the two physical channels - the central conducting wire and the metal layer - that run along the same axis.
Coaxial cables are thicker and more durable than most network cables, making them ideal for areas that are potentially exposed to the elements. They also tend to last longer than more delicate fibre optic and twisted pair cables, and are less likely to incur damage from being bent or twisted. On the other hand, while theoretically capable of relatively high-speed data transfer, they are less effective over long distances.
They were once popular for use in networking equipment, but have been gradually superseded by Ethernet, which is generally cheaper to purchase and install. They are still often used to run data from a central hub to TV, cable boxes and cable modems, and are commonly found in domestic homes.
At a glance
Strengths: Durable, high bandwidth, good resistance to EMI and RFI.
Weaknesses: Rigid, bulky, less effective over long distances.
Use for: Television connections, digital conversions, external network cabling.
Buy Coaxial cables from industry leading manufacturers
Ethernet Patch Cable
Patch cables are generally used to connect two different devices together over a short distance – for example, connecting your computer to a DSL router or hub. They generally - though not exclusively - take the form of Ethernet cables. Because they can connect a wide variety of common household and business networking components, they are among the most popular network cables on the market.
The most common forms of patch cable are CAT Ethernet cables. They take the form of Twisted Pair cable types, and offer successively higher transmission rates. The most common are CAT 5, CAT 5e and CAT 6, although CAT 7 and CAT 8 are also available for ultra-fast data transfer. A good quality CAT 5e Cable made to the proper standards is generally sufficient for most purposes, including achieving a Gigabit signal in your network.
Ethernet cables are generally not suitable for long-distance data transfer, as they are easily damaged and signal can become compromised.
At a glance
Strengths: Inexpensive, versatile, fast data transfer.
Weaknesses: Easily damaged, vulnerable to signal interference, not suitable for long-distance data transfer.
Use for: Connecting multiple devices to a central hub or router, general short-distance networking.
Buy Ethernet Patch cables from industry leading manufacturers
Ethernet Crossover Cable
Where an Ethernet Patch Cable is used to connect different kinds of devices to each other, an Ethernet Crossover Cable is more suitable for connecting two similar devices - usually desktop computers and/or laptops - by reversing (or ‘crossing over’) their respective pin contacts.
For most Ethernet communications, a router or hub will work as an intermediary to connect the transmit pins from one device to the receive pins on the other. When you connect two computers directly, you will often need a cable that can do this job itself.
More modern devices tend to perform the function of a crossover cable automatically, negating the need for them. However, they may still be necessary if you wish to test one computer by examining its behaviour at another, backing up or transferring data directly between two devices or in situations when an external hub is incapacitated or unavailable.
At a glance
Strengths: Simple, inexpensive, no internet connection required.
Weaknesses: Easily damaged, difficult to expand beyond two devices, not always compatible with gigabit transmission speeds.
Use for: Connecting two similar devices, file sharing, compensating for internet downtime.
Buy Ethernet Crossover cables from industry leading manufacturers
Power Line Communication
Power cables have not traditionally been used for networking applications, but in recent years advances in Power Line Communication (PLC) have enabled existing electrical power wires to be used to transfer and control data. This means that it is possible to charge a device and receive data from it solely using power cables rather than Ethernet, fibre-optic or coaxial.
There are two major forms of Power Line Communications - Narrowband and Broadband. Narrowband works at lower frequencies and data rates (3-500 kHz, up to 100s of kbps), but have a longer range which can be extended with the use of repeaters. Broadband PLC operates at higher frequencies and data rates (1.8-250 MHz and up to 100s of Mbps) and are generally used in short-range applications.
Common uses of PLC include short-range internet distribution and home networking. Many 'Smart Meters' - devices used to pre-program and remotely control a range of household appliances - are run through PLC. They are also used in the automotive industry to facilitate vehicle network communication of data, voice and video signals by digital means over Direct Current (DC) battery.
At a glance
Strengths: Affordable, flexible, versatile.
Weaknesses: Limited frequency, inconsistent performance over longer distances.
Use for: Smart networks, managing appliances, home and office networking.
Know Your Network Cable. Date published: 14th August 2015 by Farnell