Ethernet: which RJ45 pins?

Aug 09, 2007 2 Replies

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martin_pentreath 18 years ago

Hi,

A fairly basic question - which pins are used to carry the Ethernet signal through the cat5 between my router and the RJ45 socket in the wall? I've used the 568B standard throughout the house. I'm asking because inevitably there is one place where I haven't got enough cables, and I want to do a non-standard kludge. If the signal requires two pairs then I can only squeeze two either signals down one piece of cat5. But if only one pair is needed I could get four signals down it.

Cheers!

Martin

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Doug McIntyre 18 years ago

Gigabit Ethernet (1000-Base-T) uses all 4 pairs.

10-Base-T and 100-Base-TX use 2 pairs.

For the slower speeds, its the pairs that are pins 1 & 2 and on pins 3 & 6 (normally the orange and green pairs for 568B).

See this for which pin is which.

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There are such things as ethernet extender boxes that for reduced speed can run ethernet over a single pair, but the max speed is around 25Mbps on those, so you are losing alot for doing that.

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Carl Navarro 18 years ago

And if you hang a switch on the end of of the cable you can get 48 ports or more on it.

Ethernet 10/100 requires two pairs.

Carl

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