Understanding Network Cables#

Network cables are the unsung heroes of the modern connected world. While we odten don’t think about them, they form the backbone of our digital communication infrastructure, enabling data transfer between devices, and connecting us to the internet. In this article, we’ll explore various network cables, including copper and optical varieties, their unique features, and how they fit into different network environments.

Copper Cables#

Cat 5 (Category 5)#

Cat 5 cables are one of the earliest standardized twisted-pair Ethernet cables. They typically consist of four twisted pairs of copper wire and support data rates of up to 100 Mbps.

Use Cases: Cat 5 cables are still used in scenarios where basic networking is sufficient. For example, in small home networks where internet browsing and file sharing are the primary activities, Cat 5 cables can provide adequate connectivity.

Cat 5e (Category 5e)#

Cat 5e cables are an enhanced version of Cat 5, providing better interference resistance and supporting data rates of up to 1 Gbps.

Use Cases: Cat 5e is commonly used in small to medium-sized business networks where higher speeds are required. For instance, a small office with multiple computers and printers connected to a central server can benefit from Cat 5e cables to ensure smooth data transfer and network performance. Most devices today which are supplied with a network cable will come with a Cat 5e cable, or better.

Cat 6 (Category 6)#

Cat 6 cables offer improved performance over Cat 5e, supporting data rates of up to 10 Gbps at shorter distances due to stricter specifications and higher-quality materials.

Use Cases: Cat 6 is ideal for high-speed networks in offices. For example, a graphic design studio where large files need to be transferred quickly between workstations can benefit from the high bandwidth provided by Cat 6 cables.

Cat 6a (Category 6a)#

Cat 6a cables are an augmented version of Cat 6, capable of supporting 10 Gbps over longer distances.

Use Cases: Cat 6a is commonly used in data centers, where high-speed connections are crucial. For instance, a data center that hosts cloud services and requires rapid data transfer between servers relies on Cat 6a cables for efficient communication.

Coaxial Cable#

Coaxial cables consist of a central conductor, insulator, metallic shield, and outer insulating layer. They are used for cable television (CATV) and broadband internet connections.

Use Cases: Coaxial cables are used to connect cable modems, satellite TV receivers, and traditional TV sets. For example, a household with a cable TV subscription uses coaxial cables to connect the cable box to the TV.

Shielded Twisted Pair (STP)#

As style of cable rather than a specific type, shielded twisted pair cables have additional shielding to reduce electromagnetic interference (EMI) and provide better signal quality. While STP does offer some significant benefit, it’s also more expensive – hence, it’s usually used only where required.

Use Cases: STP cables are used in environments with high EMI, such as industrial settings. Consider a factory with heavy machinery where precise control signals need to be transmitted without interference; STP cables would be essential in this scenario to maintain signal integrity.

Unshielded Twisted Pair (UTP)#

Again, a style rather than a specific type of cable, unshielded twisted pair cables are the most common type of Ethernet cable, consisting of pairs of twisted wires with limited or no shielding. In low EMI environments this is no problem.

Use Cases: UTP cables are used in almost all Ethernet networks and are suitable for most scenarios. For example, in a typical office environment with computers, printers, and phones connected to a network switch, UTP cables ensure reliable connectivity.

Specialized Copper Cables#

Direct Burial Cables#

Direct burial cables are designed for outdoor use and are resistant to environmental factors like moisture and UV radiation.

Use Cases: Direct burial cables are used when running network connections underground between buildings. For instance, a university campus might use direct burial cables to connect different academic buildings buried beneath walkways and landscaping.

Plenum Cables#

Plenum-rated cables are fire-resistant and suitable for installation in air handling spaces in buildings.

Use Cases: Plenum cables are used in commercial buildings where there’s a need to run cables through air ducts. For example, a large office complex with a central HVAC system might use plenum cables to maintain fire safety compliance while connecting various offices.

Optical Cables (Fiber Optic)#

Fiber Optic Cables#

Fiber optic cables transmit data as pulses of light through glass or plastic fibers, providing extremely high data transmission speeds and long-distance capabilities.

Use Cases: Fiber optic cables are used in high-speed, long-distance networks. For example, a telecommunications company building a high-speed internet backbone network connecting cities across a region would rely on fiber optic cables to transmit data over vast distances efficiently.

Cable Terminations - T568A and T568B#

T568A and T568B are two standard wiring schemes used to terminate Ethernet cables with RJ-45 connectors. These schemes define the order in which individual wires within the cable are connected to the pins on the RJ-45 connector. Proper termination is crucial for ensuring that network cables function correctly and devices can communicate effectively. Let’s delve into the specifics of each standard:

T568A Wiring Standard#

T568A is one of the two common wiring standards for Ethernet cables. In the T568A scheme, the individual wire colors are arranged as follows:

  1. White/Green

  2. Green

  3. White/Orange

  4. Blue

  5. White/Blue

  6. Orange

  7. White/Brown

  8. Brown

In T568A, pins 1 and 2 on the RJ-45 connector correspond to the white/green and green wires, respectively, while pins 3 and 6 correspond to the white/orange and orange wires. This arrangement may appear somewhat random at first glance, but it’s essential to maintain consistency for proper connectivity.

T568B Wiring Standard#

T568B is the other widely used wiring standard for Ethernet cables. In this scheme, the individual wire colors are arranged as follows:

  1. White/Orange

  2. Orange

  3. White/Green

  4. Blue

  5. White/Blue

  6. Green

  7. White/Brown

  8. Brown

T568B has a slightly different arrangement compared to T568A, but it’s equally valid. In this standard, pins 1 and 2 on the RJ-45 connector correspond to the white/orange and orange wires, while pins 3 and 6 correspond to the white/green and green wires.

The choice between T568A and T568B largely depends on the networking environment and the conventions followed by a particular organization or region. It’s crucial to maintain consistency within a network, using one standard consistently throughout to ensure proper connectivity. If you mix wiring standards within a network, you can run into issues where devices don’t communicate effectively due to crossed or mismatched connections.

For example, in the United States, T568B is more commonly used in residential and commercial installations, while T568A is often used in some European countries. In practice, either standard can work effectively as long as it’s used consistently across all cables in a given network.

While it may not be the most interesting topic, understanding and correctly implementing T568A or T568B wiring standards is a fundamental skill for network technicians and IT professionals. It ensures that Ethernet cables are terminated correctly, allowing for reliable data transmission and network connectivity. Whether you’re setting up a new network or troubleshooting connectivity issues, familiarity with these standards is essential.

Final words#

In this article we looked at some of the most common types of network cable – there are of course others which we haven’t mentioned, but this list currently covers the types you’re most likely to meet in the field. Each cable has distinct characteristics and use cases, making them suitable for various networking scenarios. Understanding these differences and knowing when to use specific cable types is essential for building efficient and reliable network infrastructures.