Making Your Own Network Cables ( Straight Through & Cross Over )

[Bigpineguy Retired]

Making Your Own Network Cables

No matter whether you're putting together a small home network, or maintaining a major network in your office, you'll need network cables. The most commonly used type is Category 5 (short: Cat5), which supports speeds up to 100 Mb/s (Megabits per second). You can either go buy Cat 5 cable in the store, or you can make it yourself.

If you decide to buy it in the store, you'll pay a premium price for the convenience, but if you only need 2 or three cables and don't foresee the need for more in the near future, or need a lot of cables right away and don't have the time to make them yourself, then this is probably the way to go.

If you decide to make your own Cat 5 cable, you'll save a lot of money in the long run, as buying rolls of cable, a baggie of RJ-45 connectors, and the necessary tools will be a lot cheaper and pay for itself in a short period of time if you have an ongoing need.

What you need...

*
Cat 5 cable - you can buy a 1000 feet roll of Cat 5 cable at computer stores and industry supply houses for somewhere between 6 and 10 cents a foot, depending on the quality. Don't be cheap, get the decent quality stuff. You don't want to end up with network problems due to bad cables. Check to make sure that the color-coding on the wires is easily recognizable.

Also pay attention to the difference between solid and stranded wire cable. Solid wire cable means that each one of the 8 wires inside the cable consists of one solid copper alloy wire. Solid wire cable is usually used for wiring inside walls as it does not flex very easily and is intended for wires that will never move. It has better conductivity than stranded cable, which means you can run ethernet over farther distances with solid core.

Stranded wire cable means that each one of the 8 wires inside the cable consists of a few dozen very fine hair-like strands that bend and flex very easily. Stranded wire cable is usually used for making patch cables because of its flexibility (the wires won't break as easily from being moved around and twisted frequently).
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RJ-45 connectors - They usually come in bags of 50, 100 etc. and cost less than a quarter each. Pay attention to the type of RJ-45 connector you get and make sure it is intended for the type of Cat5 wire you're using. There are two different kind of RJ-45 connectors, depending on whether you use them with solid or stranded wire cable as mentioned above. Using the wrong kind with the wrong cable will most likely result in a bad connection.
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Crimping tool - While this is the expensive part of making your own cables, it's only a one-time startup cost. They run anywhere from 10 to 50 bucks depending on the quality and features. Keep in mind that the crimpers will pay for themselves after you make a few cables. A good crimping tool has a pair of wire cutters built in, as well as a blade to strip insulation. It also might support crimping of other connectors such as RJ-11.
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What type of cable do you want to make?

Straight through cables



There are two types of network cables commonly used in PC networks - Straight-through and cross-over.

Cross-over: A cross-over cable is used to connect two computers via their NICs, without using a hub or switch. (Note: You can only connect two computers at one time, connecting three or more will require a hub or switch of some sort).



Straight-through: A straight-through network cable is just what the name implies, a cable that passes data straight through from one end to another. Straight-through cables are used for a variety of connections. (e.g. connecting a computer to a hub or switch, connecting a computer to a cable/ISDN/DSL modem, and linking switches and hubs together.)

Let's start with a straight-through cable and then we'll get fancy with a cross-over cable.



Cutting, Stripping, And Sorting The Wires

Cut a piece of Cat 5 as long as you need. When you cut, remember the old saying: Measure twice, cut once. Make sure the cut on each end is clean and straight.
http://i119.photobucket.com/albums/o155/bigpineguy/cat5diy4.jpg

[Bigpineguy Retired]

Strip about an inch of the insulation off the cable. Cut it back nice and square. Some crimping tools such as the one used in this article come with a built-in wire stripper. You put the cable in to a stop on one side of the cutter. It will cut the jacket the right length to make a perfect crimp. It is extremely important that you only cut the plastic insulation/jacket and not the wire. Damaging one of the 8 wires, even if you just nick it or partially cut it, will ruin your cable.
http://i119.photobucket.com/albums/o155/bigpineguy/cat5diy5.jpg

Untwist the wires. You'll notice that there are 4 pairs of multi-colored wires inside. Sort the pairs by color. You should end up with wires color coded as follows: blue/blue-white, orange/orange-white, green/green-white, brown/brown-white.

Note: Some Cat 5 cable skimps on the color-coding and you will have to keep the track of which wire was wrapped around which. If at all possible, check the cable before you buy and make sure the color-coding is easy to recognize. If not, you'll be cursing up a storm later and wish you would have spent the extra 5 bucks on the better cable.
http://i119.photobucket.com/albums/o155/bigpineguy/cat5diy6.jpg

Now align the wires in the following order from left to right. The order is important since there is a wiring standard defined by the Telecommunications Industry Association (TIA) Code:

http://www.tiaonline.org.
It's called the EIA/TIA-568 Commercial Building Telecommunications Wiring Standard, and you can find more information on it here: Code:

http://www.digital-delivery.com/Standards.htm#s5


Get the wires lined up and nice and straight. Then clip off the top millimeter so that they are all the same length and stick out about half an inch from the insulated part.
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Attaching the RJ-45 Connector



The best way to insert the cable into the RJ-45 connector is this:



* Hold an RJ-45 connector so that the plastic release clip is facing away from you, and the opening for the wires is pointing down.
* While squeezing the cable so that the jacket does not move on the wires, insert the sorted and aligned wires carefully into the RJ-45 connector partway. You'll feel some resistance as the wires enter the grooves in the connector.
* Looking at the side of the connector that's facing you (should be the one without the clip), verify that the wires are still in the correct order. Sometimes the act of pushing the wires into the connector can cause the order of the wires to be switched at the last moment. Use a magnifying glass if needed.
* Push the wires the remaining way into the connector. Make sure that the wires have gone all the way into the connector and are touching the end of the RJ-45 connector. You should see a line of 8 bare wire ends. If one is missing and that individual wire hasn't gone far enough into the connector, pull the wires out, line up the ends and put them in again. You can't see this problem from the side - you can only see it from the end.
* Now push the jacket as far as it will go into the connector.



Getting all of the wires lined up and inserted correctly can be a little tricky, so take your time. This gets easier as you get the feel of it.

[Bigpineguy Retired]

If everything went well, it should look like this:

Right:
http://i119.photobucket.com/albums/o155/bigpineguy/cat5diy8.jpg
http://i119.photobucket.com/albums/o155/bigpineguy/cat5diy9.jpg
right way of wiring network cable

correct way to wire NIC

See how the end of the insulation sits snug inside the RJ-45, and how the wires go all the way to the end?

Below are two examples how it should NOT look. In the example on the left the wires were left too long, which leaves wires unprotected between the RJ-45 and the insulation. In the example on the right, the wires were cut too short and now don't reach far enough to make contact.

Wrong!
http://i119.photobucket.com/albums/o155/bigpineguy/cat5diy10.jpg
http://i119.photobucket.com/albums/o155/bigpineguy/cat5diy11.jpg
wrong way of wiring network cables

wrong network cable

Double-check one last time that the wires are aligned correctly and all the way in. Then insert the RJ-45 connector into the appropriate opening of the crimping tool. Give the handle a nice, tight squeeze without crushing the RJ-45. If you have purchased a pair of ratchet type crimpers you will know that you are done when they release. If you bought a cheap-o pair, check to make sure that all of the little metal contacts are even and at the same height below the plastic of the plug.

[Bigpineguy Retired]

using a crimping tool
http://i119.photobucket.com/albums/o155/bigpineguy/cat5diy12.jpg
Now repeat this entire procedure to put an RJ-45 plug on the other end of the cable. Use the exact same wiring scheme as on the first end, which will make it a straight-through cable.

Note: If you decided to spend a couple extra bucks on the strain relief sleeves, be sure to put them on and facing the correct direction before you crimp the second end.

[Bigpineguy Retired]

Making Your Own Network Cables ( Crossover Cable ) Introduction
This document shows how to properly construct a Crossover network cable. This cable can be used to directly connect two computers to each other without the use of a hub or switch. The ends on a crossover cable are different from each other, whereas a normal 'straight through' cable has identical ends. Their uses are shown in the following diagrams.

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Crossover cable use

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'Straight Through' cable use


Typically the ports on a hub are MDIX ports. This allows the machine at the other end to utilize its MDI Port (which is what typically a NIC card uses) without the need for a crossover cable. When I say that the ports on the hub are MDIX ports, what I mean is that one of the functions of the hub is to automatically perform the crossover functions, which are required to properly align the cables with each other. When no hub or switch is used, your cable itself must physically perform these crossover functions.

To expand on this a little, when using a hub or switch, the Transmit wires on the workstation need to be connected to the Receive wires on the hub; likewise, the Receive wires on the hub need to be connected to the Transmit wires on the workstation. But if you remember what we stated earlier - cables which are run from PC to Hub are 'straight through' type cables. This is because the hub is providing the required crossover functions internally for you. Thus, when you connect two machines together without the use of a hub or switch, a crossover cable is required - because both 'ends' are essentially the same - a NIC Card. The crossover function must take place somewhere, and since there is no hub or switch to do it for you, the cable must.

Now that we know what a crossover cable is for, let's talk for a few about types of cabling. The two most common unshielded twisted-pair (UTP) network standards are the 10 Mbit (10BASE-T Ethernet) and the 100Mbit (100BASE-TX Fast Ethernet). In order for a cable to properly support 100 Mbit transfers, it must be rated Category 5 (or CAT 5). This type of low loss extended frequency cable will support 10 Base T, 100 Base-T and the newer 100VG-AnyLAN applications. Other types of cabling include Category 3 which supports data rates up to 16 Mbps, and Category 1 which only supports speeds up to 1Mbps. The cable we are about to make is considered Category 5, and will work on both 10 Mbit and 100 Mbit systems, assuming all components used (cables and jacks) are rated for Category 5.



What you need


Cable - Be sure the cable(s) you are using is properly rated for CAT 5. It should state clearly on the jacket of the cable, what it is rated at. One option that you have when selecting your cable is to use a pre-made normal 'straight through' cable, and simply whack off one of the ends, and replace with a new "Crossed Over" end. For the purpose of this article, though, we aren't going to go that route. We are going to make the whole thing from scratch - using bulk CAT 5 cable.

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Keep everything within hands reach of you...


Connectors - Crossover cables are terminated with CAT 5 RJ-45 (RJ stands for "Registered Jack") modular plugs. RJ-45 plugs are similar to those you'll see on the end of your telephone cable except they have eight versus four contacts on the end of the plug. Also, make sure the ends you select are rated for CAT 5 wiring. There are also different types of jacks which are used for different types of cabling (such as Solid Core wire). Make sure you buy the correct jacks for your cabling.

Crimper - You will need a modular crimping tool. My advice on what brand to get? Well, I really don't have a preference at this point, but make sure you buy a good one. If you spend about 40 to 50 bucks, you should have one that will last ya a lifetime. Spend 10 to 20 bucks, and you might be able to make a few cables with it if you're lucky. You definitely get what you pay for when it comes to crimpers!

Stripper - No I'm not talking about what Spot had at his bachelor party, I am talking about a tool to strip the ends off the wires you pervert! There are several specialized tools, which can be used to strip the jackets off of cabling. If you do not have access to one of these tools, cautious use of a razor blade or knife should work just fine - but keep in mind if you go the razor blade / knife route, extra special care must be used as to not damage the wires inside the jacket.

Cutters - You need a pair of cutters that will allow you to cut a group of cables in a straight line. It is very important that all the wires are the same lengths, and without proper cutters, this can be a difficult task.



Doing the deed
You now know what crossover cables are used for. You know why you need one. You also know what you need to make one, so I guess we're ready... First thing you will want to do it cut off the appropriate length of cable that you will need. Be sure that it is plenty long enough. If you screw up, and don't cut it long enough, you will have to start all over, and you will not only waste you time, but cable and the RJ-45 ends as well. If you are pulling this cable through a wall, or ceiling, make sure the pulling is completed first. It is much more difficult to pull a cable with the ends already on it. So you have all the parts, you understand the concepts, and you have your cable, lets get started!

Baby steps...

1) - Start by stripping off about 2 inches of the plastic jacket off the end of the cable. Be very careful at this point, as to not nick or cut into the wires, which are inside. Doing so could alter the characteristics of your cable, or even worse render is useless. Check the wires, one more time for nicks or cuts. If there are any, just whack the whole end off, and start over.
http://i119.photobucket.com/albums/o155/bigpineguy/step1.gif

[Bigpineguy Retired]

2) - Spread the wires apart, but be sure to hold onto the base of the jacket with your other hand. You do not want the wires to become untwisted down inside the jacket. Category 5 cable must only have 1/2 of an inch of 'untwisted' wire at the end; otherwise it will be 'out of spec'. At this point, you obviously have ALOT more than 1/2 of an inch of un-twisted wire, but don't worry - well take care of that soon enough.

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3) - Up to this point, things have been pretty easy. Things will get a little bit tricky here, but don't worry, we'll get through this together. We are at a point in this article where a decision needs to be made. You need to decide which end of the cable you are making at this point in time. If you are making your cable from scratch like I am doing while writing this article, you have 2 end jacks, which must be installed on your cable. If you are using a pre-made cable, with one of the ends whacked off, you only have one end to install - the crossed over end. Below are two diagrams, which show how you need to arrange the cables for each type of cable end. Decide at this point which end you are making and examine the associated picture below.

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568a - standard end
(you will need one of the ends on your cable to look like this)
http://i119.photobucket.com/albums/o155/bigpineguy/568a_crossed.gif
Crossed over end wire pattern(you will want the other end to look like this)

Begin to untwist the twisted exposed wires on your cable. Use caution so that you do not untwist them down inside the jacket. Once you have all the wires untwisted begin to arrange them in the proper order based on the pictures above. This stage can be a pain in the ***, especially some of the middle wires. Once you get all the wired arranged in the proper order, make sure your wire cutters are within reach then grasp them right at the point where they enter the jacket. Make sure you keep them in the proper order! Grab your cutters now. Line them up along your prepared wires about 1/2 inch above the jacket. Be sure at this point that you are both 1/2 inch above the jacket, and that your cutters are aligned straight across the wires. You want to make a clean cut here - also make sure you don't let go of that jacket / wires!

http://i119.photobucket.com/albums/o155/bigpineguy/step3.gif

[Bigpineguy Retired]

4) - Don't worry. From this point forward things get a lot easier. Grab your jack, and begin to slide the wires into the jack. Once you get to the point where the jacket begins to enter the jack things might get a little tough, but just have some patience and hold onto those wires. It will fit in there just fine. Once it is in as far as it will go the wires should extend almost to the front of the jack, and about 3/8 of an inch of the jacket will be inside the jack. Like the pictures below.

http://i119.photobucket.com/albums/o155/bigpineguy/step4.gif


5) - Grab those crimpers - because not all crimpers are exactly the same your pictures may not match exactly what you see below. Be sure to keep a good grip on that jack and the cable. Insert the jack into the crimper. It should only go in one way, so you don't have a whole lot to worry about inserting it. Begin to compress those crimpers. You will more than likely hear a clicking sound. Keep squeezing. If you try to let go to early, nothing will happen. They will not release. Keep going until they stop clicking / stop moving all together. At this point, you should be able to let go of the jack, and the crimpers. The crimpers should release now leaving you with a crimped jack. If the crimpers do not release, you probably are a wimp and didn't press hard enough. Go ask your mom to help you at this point. She can probably finish what you started.

http://i119.photobucket.com/albums/o155/bigpineguy/step5a.gifhttp://i119.photobucket.com/albums/o155/bigpineguy/step5b.gif
Insert the jack into the crimper Crimp it! Crimp it good!


6) - It's time to examine what we have done. If you look at the end of the jack (distal), you should see that the copper connectors should not be pressed down into the wires. Toward the back of the jack (where the jacket meets the jack) it should be crimped securely holding the jacket / cable in the jack. If something has gone wrong, don't worry, its not the end of the world. Grab those cutters, and just whack the whole jack off and start back at step 1 (a pain in the *** I know, but its better to have a cable that works, than to spend hours trouble shooting your PC trying to figure out why you can't see the other machine). If everything is cool, all you have to do now is make the other end of the cable (unless you are using a pre-fab cable and have whacked one of the ends off), so go back to step one, and make the other end now.

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In closing
You should now have a fully functional CAT 5 Crossover cable. It's a good idea to label it as such, especially if you have a lot of other cables lying around. So what are ya waiting for... install the cable and test it out. If it doesn't work, double-check the ends. There is always a possibility that you have overlooked something. If so just whack the bad end and make new one. Remember the more jacks you install, and the more cables you make, the easier it gets. It's really not that hard to do, the first time is definitely the most difficult.

Here are a few other things to keep in mind...

* Maximum Cable length for including connectors is 100 meters (or about 328 feet)
* Do not allow the cable to be sharply bent, or kinked, at any time. This can cause permanent damage to the cables' interior
* Do not overtighten cable ties
* Do not use excessive force when pulling cable through floors, walls or ceilings
* Do not use staples to secure category-5 cable, use the proper hangers, which can be found at most hardware stores

[torpainter]

Excellent work.BPG!