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This document I have inherited and do not know the aut hor but it is useful information and sil ly to re-draw, but if 

this is your document please contact us! 

Nov 2004 - It looks like this document originally came from bluemax.net, see their Techtips page where you can find 

more similar useful documents too. 

The TX (transmitter) pins are connected to corresponding RX (receiver) pins, with plus to plus and minus to minus. Across-over cable must be used to connect units with identical interfaces.When straight-through cables are used to connect Ethernet devices, one of the two units must, in effect, perform thecross-over function. This is the reason that straight through cables work directly between hubs or switches and NICcards.... the Hub or Switch is designed so that their RJ45 Jacks are pre-wired with the transmit and receive pairsalready reversed. 

There are two colour-code standards in common use: EIA/TIA 568A and EIA/TIA 568B. These standards derive fromTELCO usage and the pairs shown correspond to four phone lines, each with its own line pair. This same wiring wasadopted for LAN standard Ethernet RJ45 wiring as well. RJ45 receptacle wiring for both standards are shown below:  

Note: Only pairs 2 and 3 are used for Standard Ethernet wiring. Pairs 1 and 4 can be used for other purposes suchas telephones or even a second separate, complete Ethernet connection. 

Straight-Through Wiring Using The 586A Standard 

EI A / TI A 5 6 8 A

WI RI NG STANDARD 

PI N   WI RE COLOUR

1  White w/Green Stripe

2  Green w/White Stripe

3  White w/Orange Stripe

4  Blue w/White Stripe

5  White w/Blue Stripe

6  Orange w/White Stripe

7  White w/B r o w n Stripe

8  B r o w n w/White Stripe

EI A / TI A 5 6 8 B

WI RI NG STANDARD 

PI N   WI RE COLOUR

1  White w/Orange Stripe

2  Orange w/White Stripe

3  White w/Green Stripe

4  Blue w/White Stripe

5  White w/Blue Stripe

6  Green w/White Stripe

7  White w/B r o w n Stripe

8  B r o w n w/White Stripe

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Page 1 of 2Ethernet Cable Colour code standards

06/24/2008http://www.dragon-it.co.uk/files/cat5_colour_codes.htm

 

 

The flat wiring diagram, above, shows the 568A colour code standard as the wiring for the PC side of the cable andthe same 568A standard for the Hub, Switch or Router side of things (assuming that the Hubs, Switches or Routersare wired internally to perform the cross-over function). The illustration depicts the wiring arrangement beforeinsertion into an RJ45 connector prior to crimping. 

Cross-Over Wiring Using The 568A to 586B Standards 

The flat wiring illustration, above, shows cross-over cable wiring using the 568A colour code standard as the wiringfor the PC side of things and the 568B standard for wiring to the other PC. Note that in both cases, all eight wires areshown but only four are actually needed. 

Pins 4, 5, 7, and 8 and the blue and brown pairs are not used in either standard. Contrary to common tech-lore andwhat you may have read elsewhere, these pins and wires are not used or required to implement 100BASE-TXduplexing. In fact, they can be used for other purposes such as a single line phones or even operating two separateEthernet channels, provided care is taken to assure that these wire pairs are isolated from the other wires. 

In practice, making actual RJ45 Patch cables is not physically that simple. The connections of the pairs to the pins inthe RJ45 jack isn't wire pair by wire pair. Instead, the orange pair of wires are not adjacent and the blue pair isupside-down. If fact...flattening out the cables in the correct order for insertion into the RJ45 jack before crimping isby far the most complex part of the job of making twisted pair Ethernet patch cables. 

One cannot use flat-untwisted telephone cable for a network cable that runs any appreciable distance. One must usea pair of twisted wires to connect a set of transmitter pins to their corresponding receiver pins. One cannot use awire from one pair and another wire from a different pair. 

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Page 2 of 2Ethernet Cable Colour code standards

06/24/2008http://www.dragon-it.co.uk/files/cat5_colour_codes.htm