Ethernet 10Base-T Crossover Cable

This howto was 'stolen' from http://www.whcs.com.au/services/xover.htm

This page describes how to make a crossover cable for an Ethernet 10Base-T network so that you can link two computers together if you do not have a network hub. Obviously the best way is to purchase a pre-made crossover cable or adaptor, however if you get stuck then at least following these instructions you can perform a temporary fix.

THIS WILL ONLY LINK TWO (2) COMPUTERS TOGETHER - for obvious reasons.

This cable can also be used to cascade hubs or other network devices. (eg connect a cable modem to your existing network hub).

First, ensure that the network cards in each PC are set-up correctly.

The diagram below shows how the wires are connected before you create the crossover cable.

Normal CAT5 cable

All of the wires are colour coded:

Pin # Color
Pin/Wire 1 White with orange stripes
Pin/Wire 2 Orange
Pin/Wire 3 White with green stripes
Pin/Wire 4 Blue
Pin/Wire 5 White with blue stripes
Pin/Wire 6 Green
Pin/Wire 7 White with brown stripes
Pin/Wire 8 Brown

Cat 5 cables are usually colour coded as per above (but I do not guarantee it), all you are interested in is Pins/Wires 1, 2, 3 and 6

Next cut (only if you do not have a RJ45 crimping tool or cannot borrow one and a RJ45 connector) cable. Give yourself a couple of feet from one end of the cable. If you do not wish to 'butcher' the cable this way then go to the end of this page. This way the re-connected part of the cable will be hidden behind your computer. Cut the outer cover back a couple of inches on each half of the cable in order to expose all of the wires. Then cut back about 1/2 an inch to expose the metal. You only need to do this with the white / orange - orange - white / green and green wires on each half of the cable.

Now it is time to splice the different wires together. The diagram below shows how the different colours should now connect. You only need to splice the wires listed below. Half of the wires are not needed for the cross-over cable.

Cross Cable

Left Cable Right Cable
white/orange white / green
orange green
white / green white/orange
green orange

Your crossover cable is now complete! Finish up the job by using electrical tape to create a seal around each exposed wire. You could solder all of the wires and heat shrink sleeve them but what the hell!

Preferred Method: (apart from buying a ready made crossover cable or adaptor)

If you do not wish to butcher the cable as per the above (and you have a RJ45 crimping tool and a RJ45 connector) then reverse the following pins/cables as described: -

Pin 1 becomes Pin 3
Pin 2 becomes Pin 6
Pin 3 becomes Pin 1
Pin 6 becomes Pin 2
Pin 4 remains the same
Pin 5 remains the same
Pin 7 remains the same
Pin 8 remains the same

There are some detailed pictures on this page of what the wiring should look like.

Ensure that all of the wires are of equal length and then insert them (carefully) into the NEW RJ45 connector. Hold the RJ45 connector with the clip to the bottom and the open end facing towards yourself, pin 1 is then on the left. Pay particular attention to the position of them in relation to the other end of the cable and the way it is wired. Push them into the NEW connector and crimp away. Your crossover cable is now complete! Ensure to mark (or attach a tag) to this cable so that it will not be confused (at some later stage) with an ordinary Cat5 fly lead.

This document is NOT copyright by WHCS as parts of it belong to other people. I would offer the other authors credit but I can't remember from whom or where I got all the pretty pictures.

 
freesco/howtos/howto_make_a_cross_cable.txt (49262 views) · Last modified: 2005/09/14 00:49 (external edit)
 
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