Data Communication Cable Types: From Cat to Fiber-Optic & Coaxial

In the datacom world, downtime is the last thing you want anyone associating with your installation job. When computer systems, internet, TV, or anything else communications-related go down, people get mad.

That’s in part why datacom structured cabling is its own beast vs. other connection products. And even though there are recurring themes, datacom cables themselves vary in terms of construction, performance, and specific use case. 

Let’s review the three data communication cable types, their subtypes, and what you must know about each to source a datacom cable supply effectively.

Data Communication Cable Types

There are three main types of network cabling: twisted-pair, fiber-optic, and coaxial. 

Each datacom cable type has a slightly different set of rules and performance criteria it plays by. However, as you learn about datacom cables, you’ll see two major performance traits pop up over and over:

Without further ado, here they are:

Twisted-Pair Datacom Cables

A twisted-pair cable consists of two insulated wires coiled around one another. It’s not just for show – the twisting reduces EMI (electromagnetic interference) from outside sources.

In datacom applications, twisted-pair is the Walmart of cabling solutions. It’s cheap, simple to use, and offers modest performance. Of course, sometimes Walmart is OK, depending on your shopping needs.

Twisted-pair cables come with various levels of protection. Depending on the environment, you may use:

• Unshielded twisted-pair (UTP) – most common form; used in many Ethernet networks
• Foiled twisted-pair (FTP) – adds thin, lightweight EMI protection
• Shielded twisted-pair (STP) – best option for environments with interference potential

Fiber-Optic Datacom Cables

The hype started years ago for fiber-optic cables because of their promised ability to move data quickly over long distances. So far, the tech has lived up to the hype.

Data transfer in fiber-optic cabling is through light rather than electronic signal, thus it’s immune to electromagnetic interference.

The core is either:

• Glass (most common for long-distance)
• Plastic (shorter distances, more flexible)

Despite the impressive performance, fiber-optic cable is lightweight and small in diameter.

Coaxial Datacom Cables

“Coaxial” means one conductor inside a second, cylindrical outer conductor. In between there’s a layer of insulation, as well as on the very outside of the assembly.

Coaxial cable offers more EMI protection and bandwidth than twisted-pair cables, but less than fiber-optic products. Coaxial also sits firmly in the middle cost-wise. This middle-of-the-road status actually hurts coaxial cables somewhat; some engineers feel it’s obsolete because it offers no major advantages.

Types of Twisted-Pair Cables

Twisted-pair cables are ubiquitous – you can find them in nearly any home or business. Most often, what you’re looking at is a Cat cable.

Cat Cables

In datacom transmissions, by far the most common twisted-pair cable category is, well, the Category – or “Cat” – cable. To the average Joe, they’re Ethernet cables. 

No matter the name, their primary purpose is to connect computer network devices:

• Servers
• Routers
• Modems
• Switches

They’re a staple of modern office and home settings (even more so than the stapler itself). 

These cables usually consist of four twisted pairs of copper wire. They come with a variety of shielding options to protect against crosstalk and EMI. 

Key performance standards for Cat cables include bandwidth capacity and data transmission speed. The numbered subcategory of the cable indicates its speed, frequency, and shielding.

*Cat6 cables support 10 Gbps up to 55m under ideal conditions, beyond which the speed defaults to 1 Gbps up to 100m. 

Much like an iPhone or PlayStation, the numbers indicate the chronological order of release. These days, you’re not likely to ever need Cat 1-4 products. Even the standard Cat 5 cable is mostly phased out, though it still exists in some legacy installations.

As the number gets higher, the product adds more speed, bandwidth, shielding, or a combination of those features. Newer versions can handle more demanding environments, but they also become more expensive and less flexible.

Industrial Ethernet

What makes an Ethernet cord “industrial” …?

An industrial Ethernet cable has the same core functionality as a standard Ethernet cable, but with a ruggedized build. This build may include extra shielding, a heavier jacket, or both.

Industrial-grade cables can endure conditions that would cause a Cat-astrophe in standard Ethernet setups, including:

• EMI
• Extreme temperatures
• Mechanical stress – i.e. impact, vibration
• Chemicals
  
  

Types of Fiber-Optic Cables

Consider fiber-optics when you need to transmit data across longer distances and have higher bandwidth needs. From there, you can narrow your choices between single-mode and multimode based on distance and speed requirements.

Single-Mode Fiber

Single-mode fiber is defined by its narrow core. Its covering is usually yellow, though you might see blue if the cable has a special use or characteristic.

This cable type transmits a single beam of focused light directly down the fiber without much reflection. This makes it best for long-distance communication, as it results in less attenuation and allows data to travel faster and further. 

Single-mode cabling is what you should use when the distance you need exceeds 500m. It requires few switches or routers mid-span, and the bandwidth capacity is practically off the charts.

Single-mode fiber is slightly more expensive due to its raw materials and manufacturing process.

Multimode Fiber

Multimode fiber cable has a wider core that can carry light signals down many paths within the fiber. It can transmit multiple data types at the same time and within the same glass core. This makes multimode products ideal for shorter distances requiring higher bandwidth, such as intra-building data and audio/visual installations.

Have you noticed an “OM” designation yet when researching multimode cables? OM (optical multimode) classifications are how you tell the differences in bandwidth and transmission traits. As the number goes up, so does bandwidth and performance. 

For now, OM3 and OM4 are the most common choices for new installations requiring high data rates over relatively long distances, particularly in enterprise and data center environments. OM5 is the new cable on the block. As the most powerful fiber-optic option, it can help futureproof your network infrastructure as bandwidth demands continue to rise.

Types of Coaxial Cables

You probably heard of coaxial cables long before you started sourcing them. They’ve been around seemingly forever in everyday applications such as:

• TV
• Phone
• Broadband connections
• Video

Each type of coaxial cable comes with specific ratings for:

• Impedance – Minimizes reflection and signal loss at connections between coaxial cables, devices, & components

• Attenuation – Signal loss over distance. Highly affected by frequency

• Max frequency rating – Indicates cable’s ability to handle faster & more complex signals without performance loss

For data communication, picking a coaxial cable typically means balancing:

• Signal integrity – influenced by the three ratings above
• Distance of cable run
• Environmental conditions
• Installation flexibility
• Cost

While the RG designations below are common, there can be variations between cable manufacturers. Also, keep in mind that some high-speed data applications are moving away from coaxial cables in favor of advanced fiber-optic or twisted-pair solutions. 

RG-6

• Impedance: 75 ohms
• Attenuation: 5.6 dB per 100m at 400 MHz
• Max Frequency: ~3 GHz

Its creators specifically designed RG-6 coaxial cable to carry higher-frequency signals than its predecessors. This allows RG-6 to support commercial and residential applications such as:

• Satellite TV
• Cable TV
• Broadband internet

Part of the secret sauce is the construction. RG-6 features better shielding compared to RG-59, which significantly improves overall signal integrity.

RG-59

• Impedance: 75 ohms
• Attenuation: ~13.2 dB per 100m at 400 MHz
• Max Frequency: ~1 GHz

Despite its rating, RG-59 coaxial cable is more common in lower-frequency use cases (under 50 MHz). This makes it appropriate for jobs where high-frequency data transmission isn’t a must:

• Closed-circuit TV systems
• Some video applications
• Security

RG-59 cabling is a low-cost solution that includes a thinner and more flexible build than RG-6. This makes it easier to install in tight spaces and shorter runs.

RG-11

• Impedance: 75 ohms
• Attenuation: ~3.7 dB per 100m at 400 MHz
• Max Frequency: ~3 GHz. 

It comes at a high price, but RG-11 coaxial cable’s traits make it ideal for long-distance service. The low attenuation – due to its thick build – makes RG-11 popular in installations for:

• Broadband internet
• Satellite
• Underground
• Across large buildings

The high performance also comes at a convenience cost, as RG-11 is less flexible and more aggravating to work with.

RG-58

• Impedance: 50 ohms (52-ohm versions also exist)
• Attenuation: ~24.9 dB per 100 m at 400 MHz
• Max Frequency: ~1 GHz.

It’s far from the modern savior for datacom assemblies, but RG-58 coaxial cable still exists in some legacy systems. Today, RG-58 is mostly relegated to: 

• Amateur radio
• Older Ethernet setups (10BASE2)

The cable's thinner and more flexible design helps users install it in tight spaces and short distances without much trouble.

Sourcing Datacom Cables From a Supplier

Understanding all three major data communications cable types – and their subtypes – can help you source quick and dependable network infrastructure. 

Each type of cable offers unique characteristics and use cases, from high-speed data transmission in data centers to low-frequency signal transfers in industrial settings. Pay attention to the key properties of each cable type so that you’re valuing the right numbers for the right application.

For more tips on sourcing cables and components of all types, grab our free e-book: