T568A/B Crossover Wiring

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 Question by Ted Riesz posted 05 Oct 2006
 T568A/B Crossover Wiring
I have seen two different pinouts for an Ethernet crossover cable that both claim to follow the T568A/B standard. One is Pin 4 to 4, 5 to 5, 7 to 7 and 8 to 8. The other is Pin 4 to 5, 5 to 4, 7 to 8, and 8 to 7. In fact I bought pre-made crossover cables that were wired the second way. (4 to 5 etc.) Why are there two different variations and which is the current standard?
 Answer by Joseph Golan posted 10 Oct 2006
Dear Ted,
It all depends on what type of network you are on. There is a different configuration for 10/100BaseT vs. 1000 BaseT ethernet

Here is a link to one of our pages that illustrates the proper crossover for these and other networks:


Joseph Golan, RCDD

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