Ethernet Cable Color Coding DiagramThe information listed here is to assist Network Administrators in the color coding of Ethernet cables.

Please be aware that modifying Ethernet cables improperly may cause loss of network connectivity. Use

this information at your own risk, and insure all connectors and cables are modified in accordance with

standards. The Internet Centre and its affiliates cannot be held liable for the use of this information in

whole or in part.

T-568A Straight-Through Ethernet Cable

The TIA/EIA 568-A standard which was ratified in 1995, was replaced by the TIA/EIA 568-B standard in

2002 and has been updated since. Both standards define the T-568A and T-568B pin-outs for using

Unshielded Twisted Pair cable and RJ-45 connectors for Ethernet connectivity. The standards and pin-out

specification appear to be related and interchangeable, but are not the same and should not be used

interchangeably.

T-568B Straight-Through Ethernet Cable

Both the T-568A and the T-568B standard Straight-Through cables are used most often as patch cords for

your Ethernet connections. If you require a cable to connect two Ethernet devices directly together

without a hub or when you connect two hubs together, you will need to use a Crossover cable instead.

RJ-45 Crossover Ethernet Cable

A good way of remembering how to wire a Crossover Ethernet cable is to wire one end using the T-568A

standard and the other end using the T-568B standard. Another way of remembering the color coding is to

simply switch the Green set of wires in place with the Orange set of wires. Specifically, switch the solid

Green (G) with the solid Orange, and switch the green/white with the orange/white.

Ethernet Cable Instructions:

Pull the cable off the reel to the desired length and cut. If you are pulling cables through holes, its easier

to attach the RJ-45 plugs after the cable is pulled. The total length of wire segments between a PC and a

hub or between two PC’s cannot exceed 100 Meters (328 feet) for 100BASE-TX and 300 Meters for

10BASE-T.

Start on one end and strip the cable jacket off (about 1″) using a stripper or a knife. Be extra careful not to

nick the wires, otherwise you will need to start over.

Spread, untwist the pairs, and arrange the wires in the order of the desired cable end. Flatten the end

between your thumb and forefinger. Trim the ends of the wires so they are even with one another, leaving

only 1/2″ in wire length. If it is longer than 1/2″ it will be out-of-spec and susceptible to crosstalk. Flatten

and insure there are no spaces between wires.

Hold the RJ-45 plug with the clip facing down or away from you. Push the wires firmly into the plug.

Inspect each wire is flat even at the front of the plug. Check the order of the wires. Double check again.

Check that the jacket is fitted right against the stop of the plug. Carefully hold the wire and firmly crimp

the RJ-45 with the crimper.

Check the color orientation, check that the crimped connection is not about to come apart, and check to

see if the wires are flat against the front of the plug. If even one of these are incorrect, you will have to

start over. Test the Ethernet cable.

Ethernet Cable Tips:

A straight-thru cable has identical ends.

A crossover cable has different ends.

A straight-thru is used as a patch cord in Ethernet connections.

A crossover is used to connect two Ethernet devices without a hub or for connecting two hubs.

A crossover has one end with the Orange set of wires switched with the Green set.

Odd numbered pins are always striped, even numbered pins are always solid colored.

Looking at the RJ-45 with the clip facing away from you, Brown is always on the right, and pin 1 is on

the left.

No more than 1/2″ of the Ethernet cable should be untwisted otherwise it will be susceptible to crosstalk.

Do not deform, do not bend, do not stretch, do not staple, do not run parallel with power cables, and do

not run Ethernet cables near noise inducing components.

Basic Theory:

By looking at a T-568A UTP Ethernet straight-thru cable and an Ethernet crossover cable with a T-568B

end, we see that the TX (transmitter) pins are connected to the corresponding RX (receiver) pins, plus to

plus and minus to minus. You can also see that both the blue and brown wire pairs on pins 4, 5, 7, and 8

are not used in either standard. What you may not realize is that, these same pins 4, 5, 7, and 8 are not

used or required in 100BASE-TX as well. So why bother using these wires, well for one thing its simply

easier to make a connection with all the wires grouped together. Otherwise you’ll be spending time trying

to fit those tiny little wires into each of the corresponding holes in the RJ-45 connector.

Overview

This section describes the network cable configuration associated with the following Ethernet LAN (Local Area

Network) standards over copper UTP (Unshielded Twisted Pair): Ethernet (10BaseT),Fast Ethernet

(100BaseTX), and Gigabit Ethernet (1000BaseT/1000BaseTx). Some of this information was derived

from Steven Nikkel's Web site.

Cable Configuration & Type

Use quality grade UTP Category 5/5e/6 networking cable, don't skimp on this. Shielded cable works also, but

isn't necessary. Bulk cable comes in many types, there are 2 basic categories, solid and braided cable. Braided

cable tends to work better in "patch" applications for desktop use. It is more flexible and resilient than solid

cable and easier to work with, but really meant for shorter lengths. Solid cable is meant for longer runs in a

fixed position. Plenum rated cable should/must be used whenever the cable travels through an air circulation

space. For example, above a false ceiling or below a raised floor.

Cable Diagram & Pin Out

There are 8 color coded wires. These wires are twisted into 4 pairs of wires, each pair has a common color

theme. One wire in the pair being a solid or primarily solid colored wire and the other being a primarily white

wire with a colored stripe (Sometimes cheap cable doesn't have any color on the striped cable, the only way to

tell is to check which other wire it is twisted around). Examples of the naming schemes used are: Orange

(alternatively Orange/White) for the solid colored wire and White/Orange for the striped cable. The twists are

extremely important. They are there to counteract noise and interference. It is important to wire according to a

standard to get proper performance from the cable. The hardware expects the cable to have certain properties,

a cable that does not fall within tolerance will cause errors and or failures. Besides, this maintains all your

cables to the standards and makes it easy to find errors and cross-over cables.

The standard for generic LAN telecommunications cabling is known as the TIA/EIA-568-A standard. It is

chartered to include criteria for planning, installation, and performance metrics that will support a multi-vendor

environment defining next-generation cabling such as Category 5e and Category 6, provide performance

specifications for hybrid and bundled cables such as "Speed Pull", and further define fiber usage including

connectors, distances and 50 micron wavelengths. This standard also specifies two wiring standards for a 8-

position modular connector (RJ45) that is used in UTP Ethernet networks. The two wiring

standards, T568A and T568B vary only in the arrangement of the colored pairs.

The diagram above describes the various color coding and pin outs for the network cabling and the RJ45

modular connector. The T568B/T568B was chosen for the straight through cable and T568B/T568A for the

cross-over cable. It is also possible to wire it the opposite way (i.e., straight through is a T568A). Your choice

might be determined by the need to match existing wiring, jacks or personal preference, but you should

maintain consistency.

The RJ45 end is a 8-position modular connector. There are a couple variations available. The primary variation

you need to pay attention to is whether the connector is intended for braided or solid wire. For braided/stranded

wires, the connector has contacts that actually pierce the wire. For solid wires, the connector has fingers which

pierce the insulation and make contact with the wire by grasping it from both sides. The connector is the weak

point in an Ethernet cable, choosing the wrong one will often cause grief later.

Ethernet Protocol Details

The following table lists various Ethernet protocol specifications and the appropriate cable type for the

associated Ethernet LAN standard.

Ethernet

LAN

Symbol

Encoding

Symbol

Rate

Data Encoding Data

Bits/Symbol

Pairs/Transmit

Channel

Number

of Pairs

Minimum

Cable

Standard (Mbaud) UsedCategory

Required

10BaseT Manchester 10 None 1 1 2 3

100BaseT4Multi-level,

2T/Hz25 8B6T 8/6 3 4 3

100BaseTX MLT-3 125 4B5B 4/5 1 2 5

100BaseT2PAM5x5

(2D-PAM5)25 None 2 2 2 3

1000BaseT 4D-PAM5 125 None 2 4 4 5 (5e)

10GBase-TDSQ128

(2D-PAM16)800

LDPC(1723,2048),

64B/65B, CRC83.125 4 4 5e (6a)