I got this information from http://cafe.ambrosiasw.com/ which is run by those great Ambrosia Software guys. That page is gone, but I found a better page with updated info: http://www.incentre.net/incentre/frame/ethernet.html

In fact, it obsoletes this page. So go there after reading this one.

Normal cables are wired like this: OR/WH - OR - GR/WH - BL - BL/WH - GR - BR/WH - BR

[img]../pictures/ethernet.gif[/img]

That's looking at the plug from the "flat" side (the side opposite the plastic tab). (Actually, it doesn't matter, as long as you're consistent about which side you look at.)

Both plugs are wired identically.

The crossover cable has the normal wiring on one plug, but the other one looks like this: GR/WH - GR - OR/WH - BL - BL/WH - OR - BR/WH - BR

Simple enough? If not, try the URL above, where they go into greater depth, and provide illustrations.

[b]More Advice[/b]

If you're going to make more than a few cables, invest in an "Ideal Telemaster". They have them at some hardware stores now. They are pretty expensive, but can save you money, because they crimp better.

I like to strip extra insulation off the cable, then arrange the wires, and then trim them all the same length. It's neater.

Test your cables by running actual data over them. I had a batch that tested against a simple wiring tester, but flaked out on data, because the plugs (the "ends") were faulty. I had to cut them all off and get refunds, then get another batch from another store.

Don't kink the cables. They mess with the electrical characteristics of the twisted pairs, and can harm data transmission. A corollary is that, after damaged ends and plugs, kinks are a likely source of cable problems. If you find this is the case, you can salvage the cable by cutting the kink out, and reusing the two segments for other purposes.

"Plenum" meets a building fire safety code for wiring that's in the ceiling (and within ducts). If you're installing overhead wire in an office, it must be plenum. If you use regular (cheap) cat5 cable, you're creating an unsafe work environment, and probably voiding the insurance. [url]http://www.wi-fiplanet.com/tutorials/article.php/3300311[/url]

To pull new cable (if you have it in a conduit) hook the old cable onto the new cable, and tape it up tight with electrical tape. Grease it up with that cable lube, and from the other end, pull on the old cable. If you're lucky, the new cable will pull through and replace the old cable.