On the surface, Ethernet cables are a rather unassuming part of any tech ecosystem. They facilitate a physical, wired local area network (LAN) connection between connected devices and routers, modems, and network switches. Ethernet network cables tend to offer faster and more reliable internet access when compared to Wi-Fi networks, making them an instrumental part of commercial and enterprise solutions the world over.
You may have noticed that Ethernet cables come in a variety of colors, ranging from blue, to yellow, and just about everything else in between. This raises the obvious question: what do these colors actually represent? As it turns out, the answer isn’t as clear-cut as, say, USB Type-A color coding is. In fact, believe it or not, Ethernet cord colors don’t represent speed, bandwidth, signal quality, or any other similar performance metric at all.
What do Ethernet cable colors represent?
It’s not what you think
The fact of the matter is that there’s no universal, mandated standard for the coloring of an Ethernet cord’s outer jacket. In other words, a red cable doesn’t convey bandwidth capabilities any more so than a black cable does. Instead, there are loose color conventions that are adhered to by organizations, network technicians and information technology (IT) personnel across the globe.
Here’s a breakdown of some of the common Ethernet coloring conventions used in professional environments:
- Black / Gray, Blue: Typically used for standard network connections (computers, printers, game consoles)
- Yellow: Often used for Power over Ethernet (PoE) devices (IP security cameras, wireless access points, VoIP phones, etc.)
- Red: Generally used for important or critical connections that must stay online at all times (servers, backup systems, firewalls)
- Green: Traditionally used for crossover connections (connecting two similar devices directly together and sidestepping a router or switch)
- Orange: Often used in data centers to bridge connections, sometimes used to denote guest networks or other specific network types
- Purple: Often used to designate specialized, non-Ethernet digital links
- White: Behind-the-scenes cabling (linking equipment rooms)
As you can see, there are several factors that play a role in which Ethernet cable color is chosen for a specific networking task. Ultimately, across data centers, server racks, and even office setups, IT technicians rely on color coding to visually demarcate individualized and specialized use cases.
QuizEthernet cables and ports
Trivia challenge
From Cat5 to Cat8 — see how much you really know about the cables keeping the world connected.
StandardsHardwareHistoryNetworkingConnectors
What is the name of the standard connector used on most ethernet cables?
Correct! The RJ-45 connector is the standard 8-pin modular plug used on ethernet cables. It looks similar to a phone connector but is noticeably wider to accommodate its extra pins.
Not quite. The correct answer is RJ-45. RJ-11 is actually the smaller connector used for telephone lines, which is a common source of confusion given how similar they look.
Which ethernet cable category was the first to officially support Gigabit speeds (1 Gbps)?
Correct! Cat5e — the ‘e’ standing for ‘enhanced’ — was the first category rated to reliably support Gigabit ethernet over 100 metres. It achieved this by reducing crosstalk compared to the original Cat5.
Not quite. The answer is Cat5e. While Cat5 can sometimes handle Gigabit connections, it is not officially rated for it. Cat5e introduced tighter specifications that made 1 Gbps reliable and standardised.
Who is widely credited as the primary inventor of ethernet technology?
Correct! Bob Metcalfe co-invented ethernet at Xerox PARC in 1973 alongside David Boggs. He later founded 3Com and went on to become one of the most influential figures in networking history.
Not quite. The answer is Bob Metcalfe, who developed ethernet at Xerox PARC in the early 1970s. Vint Cerf is known for co-creating TCP/IP, while Tim Berners-Lee invented the World Wide Web — both different innovations entirely.
How many individual wires are contained inside a standard Cat5e or Cat6 ethernet cable?
Correct! A standard ethernet cable contains 8 wires arranged into 4 twisted pairs. The twisting of each pair is a deliberate design choice that helps cancel out electromagnetic interference and reduce crosstalk between pairs.
Not quite. The answer is 8 wires, grouped into 4 twisted pairs. The twisting isn’t random — each pair is twisted at a slightly different rate to minimise interference between them, which is key to maintaining signal integrity.
What maximum data transfer speed is Cat8 ethernet cable rated to support?
Correct! Cat8 is rated for speeds up to 40 Gbps over distances of up to 30 metres. It was designed primarily for data centre environments where extremely high-speed, short-range connections are essential.
Not quite. Cat8 supports up to 40 Gbps, making it the fastest standardised ethernet cable category available. It operates over shorter distances than older categories and is mostly used in professional data centre settings rather than homes.
What does the term ‘PoE’ mean in the context of ethernet networking?
Correct! Power over Ethernet (PoE) allows ethernet cables to carry electrical power alongside data. This is widely used to power devices like IP cameras, VoIP phones, and wireless access points without needing a separate power cable.
Not quite. PoE stands for Power over Ethernet. It is a genuinely useful technology that lets a single cable deliver both data and electricity to a connected device, simplifying installation and reducing cable clutter significantly.
In what decade was ethernet first commercially introduced to the market?
Correct! Although ethernet was invented in the early 1970s at Xerox PARC, it was first commercialised in the 1980s. The IEEE 802.3 standard was published in 1983, which paved the way for widespread commercial adoption.
Not quite. Ethernet was commercially introduced in the 1980s. While Bob Metcalfe’s original ethernet memo dates back to 1973, it took until the early 1980s and the publication of the IEEE 802.3 standard for it to reach the commercial market.
What wiring standard is most commonly used for ethernet patch cables in home and office environments?
Correct! T568B is the most widely used wiring standard for ethernet patch cables in North America and most of the world. While T568A is also a valid standard and preferred in some government installations, T568B dominates in homes and offices.
Not quite. The answer is T568B, which is the dominant wiring standard for ethernet cables globally. T568A and T568B differ only in the arrangement of the orange and green wire pairs — as long as both ends of a cable use the same standard, the cable will work correctly.
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As mentioned, colored cables don’t represent technical differences between cords. Instead, in order to stay on top of network speed and bandwidth capabilities, you’ll have to make note of the category rating printed on the cable jacket itself. Ethernet cables are sorted into categories based on maximum speed, bandwidth, shielding, and distance limits.
Here’s a breakdown of some of the main Ethernet categories:
- Cat3: 10 Mbps speed, 16 MHz bandwidth
- Cat5: 100 Mbps speed, 100 MHz bandwidth
- Cat5e: 1 Gbps speed, 100 MHz bandwidth
- Cat6: 1 Gbps speed, 250 MHz bandwidth
- Cat6a: 10 Gbps speed, 500 MHz bandwidth
- Cat7 / Cat7a: 10 Gbps speed, 600 MHz to 1 GHz bandwidth
- Cat8: 25 Gbps to 40 Gbps speed, 3 GHz bandwidth
For most domestic use cases, Cat5e or Cat6 is more than sufficient, capable of providing gigabit internet speeds. Cat8, meanwhile, is ideal in data center contexts, capable of supporting high-bandwidth racks and the like.
It’s worth noting that Cat8 features a significantly shorter maximum length of 98 feet (30 meters) when compared to the 328 feet (100 meters) of Cat5e/Cat6/Cat6a, owing to signal weakening (attenuation), interference, crosstalk, and other factors.
So, then, Ethernet color coding is less about technical specifications and more about pragmatism. There’s no need to worry about which color cord you have hooked up in your home office — instead, focus on the cable’s respective category rating to determine performance and speed. A gray or white cable is a safe bet for blending into building decor, but a blue or yellow Ethernet cord is capable of getting the job done all the same.
