Coaxial vs Ethernet cable - What's the Difference?

Figure 1.  Axis of a circle

So it’s a line that runs right through the middle of a circle. A cylinder also has symmetry, and so it also has an axis. Cylinders are important to this conversation because a cross-section of a wire is shaped like a cylinder. We attempt to show the axis of a cylinder in Figure 2.

Figure 2.  Axis of a cylinder

Other shapes and objects have symmetry also, so they also have an axis with respect to that symmetry. But because of the pressure building inside my bilaterally symmetrical brain, that’s all I’m going to say about symmetry.

So the axis of a cable is the imaginary line that runs down the center of the length of cable. Now, how do two conductors in the same cable share an axis? One of the conductors, called the center conductor, goes right down the axis of the cable. The other conductor, called the outer conductor or the shield, wraps around an insulating material called a dielectric, which spaces the shield an equal distance away from the center conductor. You can get an idea of this arrangement from Figure 3. In cross-section, you can think of the center conductor as a line, and the outer conductor as a circle, and they both share the same axis!

Figure 3.  Structure of a coaxial cable

RG6 Coaxial Cable Types

Aside from the typical differences between indoor and outdoor communications cable where the cable jacket itself dictates the installation environment, coaxial cable comes in dual shield (DS) and quad shield (QS) variants depending upon the EMI/RFI/ESD (Electromagnetic / Radio Frequency Interference & Electrostatic Discharge) present.  More interference?  Opt for the quad shield.  Do you have an outdoor installation potentially subject to greater ESD events?  Opt for the quad shield RG6.  Quad shield RG6 is only nominally more expensive per foot than the dual shield variant but is thicker and more challenging to terminate.  Weigh your options!  Both variants are considered shielded cable and the cable shielding must be bonded to ground for optimal performance and equipment protection.  For more information on the correct cable jacket for your installation, please see Facts About Ethernet Cable Jacket Ratings.  For a more detailed look at the differences between quad and dual shield coaxial cable, please see The Difference Between Dual Shield vs Quad Shield Coaxial Cable.

Coaxial Cable Applications and Speed

Most of the time, coaxial cable is seen and referred to as coaxial Internet.  Coaxial cable is used for many applications however:

• Data (proprietary data transmission, not typically Ethernet packets)
• Video applications
• Voice transmission
• Radio-frequency antenna installations
• Cable television and HDTV
• Satellite antenna installations
• Broadband Internet

Although capable of transmitting Ethernet packets, RG6 coaxial cable is very slow as it works with a single conductor circuit, reaching a maximum speed of 10Mbps at the peak of coaxial use for LANs applications.  

The 10BASE-T Ethernet standard made the switch to twisted-pair cable in 1990. For your entertainment, a backwards-compatible network card from that period is shown in Figure 4.

 Figure 4.  Network interface card with both coaxial and twisted pair connectors

Speed needs have dramatically increased over time, effectively making coaxial cable obsolete for Ethernet applications (not counting hybrid use cases such as MoCA).  As such, coaxial cable is not used any longer for purposes of Ethernet data packet transmission.   For more information on hybrid MoCA installations, please see MoCA vs. Ethernet.

Enter copper twisted pair Category cable, a cable designed specifically to carry Ethernet data!

Ethernet Cable Construction

Balanced twisted pair Category cable is commonly referred to as “Ethernet cable” or “network cable.”  How is it different from coaxial cable? In just about every way except they both usually contain copper. There is nothing in a twisted pair cable that shares an axis with anything else. In fact, it is the cable’s complete lack of symmetry that gives it its most valuable property. It is made of four pairs of insulated conductors. The conductors of each pair are twisted around each other (Figures 5, 6).

Figure 5.  The four pairs of conductors in a balanced twisted pair cable 

Figure 6.  Cross section of balanced twisted pair cable

Not only is each pair twisted, but each pair is twisted at a different rate (twists per inch). That way, conductors within the cable are rarely, if ever, oriented parallel to any other conductors inside the cable, or outside. This allows the conductors to avoid noise and signal loss due to electromagnetic interference (EMI).

More about this can be found in our Cable Academy blog, Why Are Wires Twisted Inside an Ethernet Cable?

Ethernet Cable Applications and Speed

Ethernet copper twisted pair Category cable is used for a dizzying array of applications such as:

• LAN (Local Area Network) data transmission for computers, printers, servers, etc.
• VoIP (Voice over IP)
• PoE (Power over Ethernet) for data and power transmission to power and connect with signage, lighting, WiFi access points, and surveillance cameras
• HDBASE-T (video specific applications)

In addition to having four conductor circuits as opposed to coaxial’s single conductor circuit, copper twisted pair Ethernet cable comes in different Categories depending upon your speed requirements.  The currently accepted TIA Categories are Cat3, Cat5e, Cat6, Cat6A, and Cat8.  Also seen is Cat7, but this is an ISO/IEC 11801 standard used outside of North America and requires unusual termination hardware such as GG45 and TERA connectors.  Ethernet data packet transmission speeds over copper twisted pair Ethernet top out at 40Gbps for Cat7 and Cat8.  This is 4,000 times faster than coaxial cable!

Like most things that are important within a culture, twisted pair cable goes by many names. In addition to twisted pair cable it is called datacom cable, network cable, data center cable, enterprise cable and category cable, but most people just call it Ethernet cable.  

Ethernet will be around for a long time to come, but like anything else we want to go faster.  Learn more on how Ethernet cabling compares to fiber optic cable here!

Frequently Asked Questions

Do you need coax cable for Internet?

That will depend upon your Internet Service Provider (ISP).  Many homes are still being serviced with coaxial cable for Broadband HDTV and Internet service, although fiber is making inroads at an increasing rate.

What are the main types of coaxial cable?

There are many different types of coaxial cable.  The old naming scheme is RGX (where X stands for the type of coaxial cable).  The new naming is Series X (where X stands for the type of coaxial cable).  The main types seen today are Series 59 (RG59), Series 6 (RG6), and Series 11 (RG11).

Is coaxial faster than ethernet?

Both coaxial cable and copper twisted pair “Ethernet” cable have their intended uses.  For some purposes, Ethernet cable is faster and for other purposes coaxial cable is faster.  For LAN data transmission making use of Ethernet switches for packet switched Ethernet  networks, copper twisted pair “Ethernet” cable is much faster.  Faster yet is fiber optic cable.

Are all coax cables the same?

At the most basic level, yes, all coaxial cables are the same.  There are two conductors forming a single circuit.  The differences are found in the amount of shielding, cable jacket, conductor materials, and thickness.

How does coax compare to fiber optic cable?

Coaxial cable and fiber optic cable both are used for data communications, but the similarities stop there.  Coaxial cable is using metallic conductors where fiber optic cable uses glass conductors.  Coaxial cable is always shielded for EMI/RFI/ESD where fiber optic cables do not need shielding (although fiber optic cables may be armored for durability, not EMI/RFI/ESD prevention).  Last, fiber optic cable uses light to transmit data where coaxial cable uses low voltage electricity.  Light transmission is much faster and can go much farther (or both).

Final Thoughts

So, if these different types of media are all used to transmit signals over Ethernet networks, why is it that only balanced twisted pair cable is called Ethernet cable? Because the vast majority of people have only ever used twisted pair cables to connect to a network.

As we said above, the 10BASE-T Ethernet standard made the switch to twisted-pair cable in 1990. That happens to be the same year that the first web browser was written at CERN, a research institution in Switzerland. The World Wide Web became available to mainstream users in 1994 with the release of the Mosaic browser, later called Netscape. Over the next two decades use of the Internet exploded to include users from all over the world with virtually unlimited content. Almost all of these users connected to their networks with twisted pair cable.

So why do I call twisted pair cable Ethernet cable? I think it’s because all of my friends do.

HAPPY NETWORKING!