What is Cat-5 Cable?

R. Kayne

Cat-5 cable, sometimes called Ethernet cable, is short for Category 5 cable, a current industry standard for network and telephone wiring. This type of cable is unshielded wire containing four pairs of 24-gauge twisted copper pairs, terminating in an RJ-45 jack. If a wire is certified as Cat-5 and not just a twisted pair wire, it will have this designation printed on the outside.

Cat 5 cable with RJ45 plug.
Cat 5 cable with RJ45 plug.

The outer sheath of this type of cable can come in many colors, with bright blue being quite common. Inside, the twisted pairs are also sheathed in plastic with a standard color scheme: solid orange, blue, green and brown wires twisted around mates that are white and striped with a solid color. The twisted pairs reduce interference and crosstalk, and they should be left twisted except at the termination point. Some experts recommend untwisting only 0.5 inch (12.7 mm) of the pairs to strip and make connections. Cat-5 cable can be purchased off a spool in varying lengths, or bought pre-cut to standard lengths with RJ-45 jacks already attached.

Cat-5 cables plug into RJ-45 ports, like those on the back of this router.
Cat-5 cables plug into RJ-45 ports, like those on the back of this router.

Cat-5 replaces Cat-3 cable, which could only carry data at speeds up to 10 megabits per second (mbps), while the newer standard cable supports data speeds of 100 mbps or more. It can also reach 300 feet (100 meters), and aside from networks and telephones, it can be used for many other purposes. Cat-5e is enhanced cable that supports 1,000 mbps or gigabit Ethernet, or it can be used with 100 Base-T networks for long-distance runs of 1,150 feet (350 meters). This type of cable meets a specific standard referred to as "EIA/TIA 568A-5," which should be stamped on the outer sheath.

Among Cat-5 cables, there are three different configurations for pinouts, or wiring of the RJ-45 connectors. Various network devices use one of the three, which are referred to as straight through, crossover and roll-over.

The cable that runs from a computer to a switch will be a straight through cable, for example. If two PCs or two switches are connected, a crossover cable would be used. A roll-over cable will connect a PC to a router. More recent devices, however, can detect the type of cable being used and route signals accordingly.

Network cable testers can be used to tell if an Ethernet cable is capable of carrying a signal.
Network cable testers can be used to tell if an Ethernet cable is capable of carrying a signal.

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Discussion Comments


Hi Anon17953 how are you? Cat-6 is the best

If you like more information skylite communication search in google


Anyone used excel? I'm looking for a reliable 5e, can sacrifice a bit of speed for reliability.


Are these "cat" cables affordable? I'm planning to buy some for my computer. What are the most durable type of "cat"? Is cat 5e an upgraded version or are these cables all the same? Help! --Mike G.


Does someone know the maximum voltage/current supported by a Cat-5?


So what's the difference between a cat 5 and a cat 5e. I was thinking of getting these cat 5 cables.


- anon62578: Cat5 cable is not obsolete but, finding the "out of style" cable might be problematic. Virtually all new nets would be 5e, 6 or fiber.

If a vendor is doing the work, they may not have cat5 on hand and might not wish to invest in a box of cat5.

If you do locate a roll, it may be as little as half the price of cat5e or cat6. Since part of your network is cat5 you would "not" be foolish to use it for a few new connections.

The problem with it is, if you need enough to buy a roll, why not start your upgrade now with cat6?

That said, one day you will wish to upgrade. Unless you plan to abandon that network soon, start upgrading now with cat6.

Avoid shielded unless you absolutely know what you are doing.


Is any Code or Standard that support the use of CAT-5-e Cable for CCTV System?


Is cat-5 cable obsolete? We have it in in our office, but are being told that Cat-5 e is the lowest we can go. Is that true?


i have 2 cctv cameras with BNC outputs. can these be put into a coaxial splitter sent down a cat5e cable over 200m? If yes what do i need to do to split the signal so i can see the images? thanks martin.


I currently use a Cat-5 cable from the original installation. Can I use a Cat-6 cable with a splitter to another computer? Thus the splitter would have a Cat-5 to original modem and the Cat-6 to the additional computer. Or do both have to be Cat-5? Thanks


Cat-6 is a newer cable standard with double the bandwidth of Cat-5.


What is the difference between Cat-5 and Cat-6 Cable?


The local telephone company network offers 7 meg DSL for customers within 7,000 feet of the central office. If cat. 3 house wire will support 10mbps and I am receiving the signal at or above 7mbps, why would I need cat. 5 wire installed at my house?

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