Tuesday, June 19, 2007

How to: Make a LAN Cable

[Its late and I'm going to bed even though I still need to edit this one more time so please excuse any errors.]

LAN cables are used to link computers together to form a network. This network is a core component of a LAN Party and LAN cables are a key ingredient in it. These cables can also called network cables, cat5 cables and other names so don't get confused.

Why make my Own?
Simple, It's cheaper. For example to buy 100 10ft cables would cost about $175 but you can make them yourself for about $100. At a LAN Party where budgets are tight this can be a great money saver. Another benefit is that you can custom size the cables for your needs so they fit "just right" and you don't have messy piles of extra cable around.

Getting Started
First you are going to need a few tools to get started:
From left to right: standard wire cutters, cable stripper for standard UTP cable, crimper for RJ45 plugs, basic CAT5e cable tester (optional). You can buy most of these at your local hardware store but it may be cheaper to buy them from a company like, a site that sells these sort of things for dirt cheap.

And some supplies

From left to right: Cat5e cable and RJ45 Connectors/Plugs.
You can also buy most of these at your local hardware store but it may be cheaper to buy them (especially the plugs) from a company like a site that sells these sort of things for dirt cheap. Ensure that the plugs match the the type of cable you're crimping. For example, stranded cable needs plugs designed for it and solid core cable needs a different type for it.

Step #1 Cut to Length

Measure out the length of the cord you want to make. Add 2 inches extra for when you strip and trim the ends before crimping it. Cut the cord using your standard wire cutters.

Step #2 Strip the Ends

The next step is to strip an inch of insulation off each end. Start by by placing the the cable in the correct spot in the wire stripper for cat 5 and spin it around few times to get a nice clean cut. If its your first time using you it, you may need to adjust the blade so that is cuts cleanly through the outer sheath without damaging twisted pairs inside. To adjust it, take a screw driver and tighten or loosen screw at tip. Its good idea to test it on a spare piece until you get the blade set right. It is better to set it too shallow than to have it cut too far and cause damage. Give the end a little twist to free insulation and then slide it off. Repeat on the other end.
Step #3 Get the Wires in Order.

There are 4 twisted pairs in a Cat5e cable, each a different color: orange, green, blue, and brown. Each pair has a solid color wire and a white wire often with a matching stripe. For example the orange pair is made up of a orange wire and a white of orange wire. It is important to keep track of which white wire belongs with each solid wire because it is hard to tell the white wire apart if things get confused. The final order of the individual wires should be white of orange, orange, white of green, blue, white of blue, green, white of brown, brown. This may sound confusing but there is an easy way of doing things.
Hold the end of the cable in your hand and bend the orange pair to the left and the brown pair to the right. Then bend green pair to the bottom and blue to the top

Then untwist each pair and smooth them out so you can start lining the wires up in the correct order. Get each pair in the right order looking from the top: white of orange should below orange; white of blue should be to the right of blue; white of brown should be above brown and white of green should be to the left of green.

Bend white of green upwards so that it sits between the orange and blue wires and then bend the green upward so that it is between white of blue and white of brown.

then gently slide the wires together so they are all parallel to each other and smooth them out

Step #4 Trim

Once the wires are in the right order, You need to trim off the excess so when crimp the cable all the individual wires are siting correctly. When your trimming you want to make sure that not only the outer sheath extends as far as possible in to the connector but that individual wires do to. First just get all of the wires even by snipping off just the wires that hang past the shortest one. then test fit the connector by sliding the row of wires into the connector (tab side down, gold side up) making sure to keep the wires flat and in order.

Then trim the excess until the outer coating can't be slid in any further. (in the picture left the wires are too long and need to be trimmed)

For the first few times it will take trial and error to get the wires in the connector correctly and get the length right, but after a while you'll get the hang of it.

Step #5 Crimp

Once the wires are all in the connector correctly (make sure you triple check the color order) insert the wire with the connector on it in to your crimper and firmly press the cable in the connector while squeezing the crimper.

Use a fair amount of pressure and hold it for a few seconds to make sure you get a really good crimp. Then give the wire a little tug to make sure the crimp is tight. If the connector comes off cut of the end and start over.

Step #6 Test

Once you get both ends crimped its time to cross your fingers and test it. for the first round i use a cheap tester I got off of eBay. You just plug in both ends and turn the tester on. On my tester both lights on each channel should light up to signal a good cable. After that I test it by connecting it to my laptop and switch to see if I can load a web page or two. If fails one these the only option is to start over.

All Done! You should now have cables that you made yourself.

Have a question? Did I leave something out? That's what the comment box is for.

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