Save Money by Making Your Own Cables

It doesn't matter if times are tough we should always be on the lookout for ways to economize as it is the savings we make in times of plenty that stand us in good stead for when the going gets rough. Making your own cables is one way to accomplish this.

Cable Tools

No matter what the job it always pays to have the right tools and when it comes to making cable this is especially true. So let us have a quick look at what tools are required. First up is a crimping tool.

Due to the design of network cabling and the RJ-45 modular plugs used as connectors a special crimping tool such as seen in Figure 1 is essential. Without it you will not be able to rapidly produce properly terminated cable of any great reliability or of consistently reliable quality.

Even though the crimper does have built-in cutters which can be used to cut the cable, individual wires, and even to strip the outer jacket, the following tools are immeasurably superior when it comes to stripping and cutting your cable to the desired length. They also make for a much cleaner professionally looking job.

A Universal UTP stripping tool (see Figure 2) is my tool of choice for stripping the outer jacket from UTP pairs.

Small diagonal cutters (Figure 3) are a tool that should be in every tool kit and are very handy for trimming and cutting wire and cables of all types.

Now for a schematic showing the correct order in which to insert the wires into the RJ-45 modular plug depending upon whether you are making a straight-thru (patch) cable or a cross-over cable (see Figure 4).

To check out if you have got it right hold both ends of your cable with the plugs facing away from you and the little clip pointing down. Pin 1 will be on the left. For a straight-thru cable the wires will be arranged in the same order. For the cross-over variety they will be different with one being the same as a normal straight-thru cable arrangement and the other as indicated in Figure 4 above on the right (under cross-over).

Now let's get down to making the cable.

Always remember the following Golden Rule:

Measure Twice - Cut Once

1. Measure the required length for your cable (from point-of-connection to point-of-connection)
2. Pull the cable off the reel to the desired length and cut
3. Strip the jacket from one end of the cable - approximately 1.25cm bearing in mind that cable diameters and jacket thicknesses can vary between cables made by different manufacturers and even between different batches from the same manufacturer. See Figure 5.

1. Inspect the wires for nicks
2. Spread and arrange the pairs roughly in the order of the desired cable end. See Figure 6.

1. Untwist the pairs and arrange the wires in the order of the desired cable end. Flatten the end between your thumb and forefinger. Trim the ends of the wires so they are even with one another. See Figure 6.
2. Insert wires into RJ-45. Hold the RJ-45 plug with the clip facing down or away from you. Push the wire firmly into the plug.
3. Inspect your construction and arrangement prior to crimping

1. Crimp Once. Hold the wire near the RJ-45 plug with the clip down and firmly push it into the left side of the front of the crimper (it will only go in one way). Hold the wire in place squeeze the crimper handles quite firmly. Only crimp once.

1. The crimper pushes two plungers down on the RJ-45 plug. One forces what amounts to a cleverly designed plastic plug/wedge onto the cable jacket and very firmly clinches it. The other seats the "pins," each with two teeth at its end, through the insulation and into the conductors of their respective wires.
2. Test the crimp. If done properly an average person will not be able to pull the plug off the cable with his or her bare hands. And that quite simply, besides lower cost, is the primary advantage of twisted-pair cables over the older thinnet coaxial cables.
3. Prepare the other end of the cable so it has the desired end and crimp.
4. Inspect. If both ends of the cable are within reach, hold them next to each other and with RJ-45 clips facing away. Look through the bottom of the plugs. If the plugs are wired correctly, and they are identical, it is a straight-thru cable. If they are wired correctly and they are different, it is a crossover cable.
5. Test the cable. If you have an operational network, test the cable. Copy some large files.
6. Troubleshooting. If the cable doesn't work, inspect the ends again and make sure you have the right cable and that it is plugged into the correct units for the type of cable. Try power-cycling (cold booting) the involved computers. Try a known working cable. If it works then you should make a new cable (if there is enough slack cut-off they RJ-45 connectors and attach new ones. RJ-45 connectors should not be reused). Of course if you have a cable tester (Figure 9) you can use it to test the cables.

1. Cable Testers. The cable tester shown in Figure 9 above is a two-part cable tester. The two parts can be detached to test spans of cabling by attaching the two parts on the two ends. Individual wires are tested in running sequential order. The more advanced models will allow you to test RJ-11 cables (telephone) too. I even have a model featuring a token ring BNC connector.
2. Labels. Always label both cable ends clearly. Once proven to be a fully functional viable cable label both ends. A portable labeller such as the one above in Figure 9 is ideal for making cable labels. Also indicate whether they are straight-through or cross-over cables (also at both ends of each cable).
3. Cable Ties. Use cable ties (see Figure 10) to tie up your cables into bunches of cables with related functionality for a neater job and to make it easier to identify cables for future troubleshooting of network reconfigurations. Some of the more expensive cable ties such as those shown in Figure 10 are reusable. So if you are trying to be as environmentally friendly as possible consider them.