Ethernet Cables and How They Work

A look at which Ethernet cables are on wired networks

Part of white keyboard and blue, red and yellow cables on it.
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An Ethernet cable is one of the most common forms of network cable used on wired networks. Ethernet cables connect devices within a local area network, like PCs, routers, and switches. These physical cables are limited by the distance that they can stretch and still carry proper signals and by their durability. These limits are one reason there are different types of Ethernet cables optimized to perform certain tasks in particular situations.

What an Ethernet Cable Looks Like

An ethernet cable resembles a phone cable but is larger and has more wires. Both cables share a similar shape and plug, but an Ethernet cable has eight wires and a larger plug than the four wires found in phone cables.

Ethernet (RJ45) and Phone cord (RJ11) jacks
Ethernet (left) and legacy phone cord (right).

Ethernet cables plug into Ethernet ports, which are larger than phone cable ports. An Ethernet port on a computer is accessible through the Ethernet card on the motherboard.

Ethernet cables come in different colors but phone cables are usually just grey.

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What is an Ethernet Cable?

Types of Ethernet Cables

Ethernet cables support one or more industry standards including Category 5 and Category 6. Most technicians refer to these standards as CAT5 and CAT6, respectively, so many online shopping carts use this abbreviated language as well.

Ethernet cables are manufactured in two basic forms called solid and stranded. Solid Ethernet cables offer slightly better performance and improved protection against electrical interference. They're also commonly used on business networks, wiring inside office walls, or under lab floors to fixed locations.

Stranded Ethernet cables are less prone to physical cracks and breaks, making them more suitable for travelers or in home networking setups.

A crossover cable is a type of Ethernet cable designed to connect two computers to each other. By contrast, most Ethernet cables are designed to connect one computer to a router or switch.

Limitations of Ethernet Cables

A single Ethernet cable, like an electric power cord, features a maximum distance capacity, meaning the cable has an upper limit as to how long it runs before signal loss (called attenuation) adversely affects performance. This problem results from the cable's electrical transmission characteristics and is directly affected by interference around the cable.

Both ends of the cable should be close enough to each other to receive signals quickly, but far enough away from electrical interference to avoid interruptions. However, this precaution alone doesn't limit the size of a network because hardware like routers or hubs can be used to join multiple Ethernet cables together in the same network. This distance between two devices is called the network diameter.

The maximum length of a single CAT5 cable, before attenuation occurs, is 324 feet. CAT6 can go up to 700 feet. Ethernet cables can be longer but they might suffer from signal loss, especially if they pass near electrical appliances.

Ethernet cable length is a little different if you're talking about thin, 10 base 2, or thick, 10 base 5 cables. The former should be no longer than 600 feet while the latter cable type should be able to reach lengths of around 1,640 feet.

A short cable may suffer from reflection. However, some people have reported no problems with cable lengths as low as 4 inches.

Different types of RJ-45 connectors serve different purposes. One type, designed for use with stranded cables, is incompatible with solid cables. Other types of RJ-45 connectors may work with both stranded and solid cables.

Alternatives to Ethernet Cables for Computer Networking

Wireless technologies like Wi-Fi and Bluetooth have replaced Ethernet on many home and business networks. These wireless technologies are especially advantageous if you'd otherwise run the cable outside or in locations with a heightened risk of wire damage.