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Cat 5 / 6 Cabling Standard and Cable Type

Since automatic detection or MDIX has been implemented in networking, a lot of people tend to ignore the very basic of networking standard.

For this reason, let us review these standards that will be explained so that we may be able to appreciate them.

The two networking standard that will be discussed here are TIA/EIA-568-A and TIA/EIA-568-B. This can be identified by the color coding used in a twisted pair wire or Cat 5. Below is the actual color coding used by the two standard mentioned earlier.


As you can see, both standard uses two pairs as interchangeable, the orange/white orange pair and the green/white green pair, and two pairs that are just in place, the blue/white blue pair and brown/white brown pair.

How is it that the blue/white blue and brown/white brown pair does not change? This is because these wires are actually not needed. What you actually need are just Pins 1, 2 ,3 and 6 in an RJ-45 Plug. Pins 4, 5, 7 and 8 are not used but it is easier to fit the 4 other wires to their corresponding pin in the RJ-45 plug if we include them.

Pin 1 - TX+ (Transmit Positive)

Pin 2 - TX- (Transmit Negative)

Pin 3 - RX+ (Receive Positive)

Pin 4 - None

Pin 5 - None

Pin 6 - RX- (Receive Negative)

Pin 7 - None

Pin 8 - None


Straight Through Cable

Crossover Cable


A Straight Through Cable is a CAT 5 Cable that has the same termination. Below are straight through cables

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Uses of Straight Through Cable

Although this is not applicable anymore due to the MDIX (Auto Sense) technology. It is proper that we should learn the uses of a straight through cable.

Straight through cable are used in connecting different devices. Example of which is connecting your personal computer or laptop to your home or office switch, switch to your home/office router. As long as you are connecting different devices then that is where a straight through cable can be used.

As long as your are connecting different devices, then you use straight through cable.


A Crossover Cable is a cable that has a different termination, thus, the name crossover. One termination is T-568 - A and the other is T-568 -B. Below are Crossover Cable


Use of Crossover Cable

Crossover cable is used when connecting similar devices. If you are connecting one personal computer to another personal computer, one router to another router, one router to several routers, one switch to another switch, or one switch to several switches, then you use a crossover cable.

Tools and Materials Needed

In order to connect devices, you need the following:

UTP (Unshielded Twisted Pair) Cable


Crimping Tool

Additionally you can add;

Wall Mount

Protective covers for jacks

For actual crimping instructions, you can find videos in youtube.

Similar information are found if you search the internet. However, I hoped that I have simplified them enough for people to fully understand them. There had been disinterest because of the highly technical way these materials are presented but by simplifying them, I hope interest would pickup.

Some say that this is already obsolete, but I aim to educate people on the most basic of things. Any troubleshooting always starts with the basic even the most complicated of problem.

Comments are welcome below.


Richard Demalata (author) from Santa Rosa, Laguna on December 16, 2013:

Comment here for questions. I'll be more than happy to answer them as soon as I see it.

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