By Bob Catanzarite
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  2001
Bob Catanzarite

 

 

 

 

 

CATx Stripping and Terminating - Chapter 1

 

In this section I'll describe the process of stripping and terminating CAT5 cabling. This process will be the same if you chose to use CAT5e cabling. I haven't researched CAT6 cabling on detail enough to describe that process yet so for the time being I'll ignore CAT6.

 

The Cable

First a brief description of the CATx cable itself. CATx is a term I use to describe CAT5 and CAT5e and CAT6.  CATx cables have 8 conductors grouped as four twisted pairs. It's the twisted pairs that are key to the ability of these cables to carry such high speeds digital signals (100 Mbps and 1000Mbps) over such a long distance of 100 meters. Some things common to CAT5, CAT5e and CAT6 cable are - they all have four twisted pairs and they all use the same color wires. See the CAT5 and CAT5e cables in the photo below. Notice how the pairs consist of a solid colored insulated wire paired with a white colored insulated wire that has a stripe of the same color as the solid wire. Note here too how CAT5 and CAT5e look so similar. CAT6 photos aren't shown here. In fact I'm not going to cover CAT6 cable or it's connectors and terminating procedures. I will likely be adding info on CAT6 soon.



(Click for a larger image)

 

For a more detailed discussion on how Ethernet and  twisted pair wiring works and why see my Links page

For all practical purposes you can work with these three CATx types in the same manner. When there is a difference I'll point that out. The two important 'rules' to remember are:

bullet    Do Not remove any more of the cables jacket than you absolutely have to.
bullet    The un-twisted part of the wires CANNOT exceed 1/2".

These rules are intended to limit how much you can untwist the twisted pairs. So lets move on.

 

The Connectors

Second here is a brief description of the RJ45 connector. The RJ45 connector is called a 'modular connector'. In the context of these connectors I don't know what the significance of the term modular is. But, whatever, the RJ45 connector looks a lot like the standard telephone connector which is called an RJ11. The RJ45 is larger than the RJ11 because the RJ45 has room for 8 conductors where the RJ11 has room for only 6 conductors.  See the photos of the two plugs below. The RJ11 is on the left and the RJ45 on the right.

The two jacks that the plugs mate with have the same conductor count and size differences.  See the photos of the two jacks below. The RJ11 is on the left and the RJ45 on the right.

      

 

The Standards

Stripping CATx cables and terminating CATx connectors is really easy but it does take some finesse, practice, time and patience. But before we get into the How To part of it lets first decide on which wiring standard to use. 

You'll likely be somewhat confused by the wiring standards. The standard called EIA/TIA-568-A describes a 'Commercial Building Wiring Standard'. Within this EIA/TIA-568-A standard are two defined wiring 'patterns' for CATx cabling: T568A and T568B. The EIA/TIA-568-A is less of a concern to someone who is wiring their home with network wiring. What is of concern to the home network are the two wiring patterns T568A and T568B. You can learn more about the EIA/TIA-568-A  standards (if your so inclined) by reading an excellent publication from Leviton called Strategies.  If this Leviton link is broken it is because Leviton constantly moves the URL for their Strategies document. If the link fails then do an internet search for 'Leviton Strategies'.

The meat of all this for the home network are the two wiring patterns. These wiring patterns are illustrated below as they apply to RJ45 plugs.

 

    

 

Here is an area that confused me for quite some time. Fortunately, there is a simple answer.

The EIA/TIA-568-A 'Commercial Building Wiring Standard' specifies TWO DIFFERENT wiring color pattern for 8-pin RJ45 connectors. One color pattern is T568A and the other is T568B as shown above. You will read that one is preferred for commercial applications and the other is preferred for residential applications. Whatever they say - the meat of the matter is that these two different looking wiring standards are ELECTRICALLY BOTH THE SAME IF you use the SAME color pattern on BOTH ends of a given cable! Irregardless of which of the two color pattern you choose pin 1 on one end is connected to pin 1 on the other end. Pin 2 on one end is connected to pin 2 on the other end and so forth. The difference is just in the COLOR of the wires. The important thing here is to decide on JUST ONE color pattern and DO ALL your wiring with that pattern you chose.

It really doesn't matter which you chose. Here's how I decided on which pattern to use. I went to my local Comp USA and bought a pre-made CAT5 cable. It was wired to the T568B standard so that is what I chose to use for ALL of my wiring. That's the simple solution - just pick one pattern and stay with it. Now that I have decided to use the T568B standard for all my wiring - if I were to go to say Radio Shack and buy a pre-made CAT5 that has been made to the T568A standard I CAN still use it just fine. I'll repeat - It doesn't matter which standard you use as long as both ends of a given cable use the same standard. The only thing to avoid here is using T568A on one end of a cable and T568B on the other end. This WILL NOT work.

CATx jacks, well at least the Leviton ones that I used, have printed on the side of them the color codes for both standards. See the photo below. The A and B on the side correspond to T568A and T568B.


(Click for a Larger Image)

So , just make your choice. I chose T568B. Let's get on to the How To.

 

The How To

Before we get too far into this process let me show you how you can dress up the looks of your CATx cables and at the same time make them more robust. A vinyl boot can be put over the cable BEFORE the RJ45 connector is crimped on. See the photo below:


 (Click for a larger image)

These boots are really nice. They are cheap - about 20 each, come in many colors and are easy to use. And you can use them to color code your cables if you wish. Just REMEMBER to put them over the cable BEFORE you crimp on the RJ45 connector. Of course the use of these boots is entirely up to your personal preference. You don't NEED these boots.

Now lets see how to terminate an RJ45 plug on the end of a CATx cable. You NEED a CATx cable stripper - they only cost around $20. The Cable Stripper is used to remove overall CATx cable jacket that surrounds and protects the paired wire conductors inside.  The stripper will help ensure that you don't nick the paired wires inside as you remove the jacket. Shown below is a photo of a typical cable stripper.



(Click for a Larger Image)

You DON'T have to strip the insulation off of the individual paired wires. Just remove about  1 1/2 inch of the jacket as shown below. The way the stripper tool shown above works is the cable is inserted into the stripper and then the stripper is rotated a couple of times allowing the tools cutting blade to score the cables jacket.


(Click for a Larger Image)

Next is to untwist the twisted paired wires. Then arrange them in the order.  Click here for a pdf version of the T568A and T568B color codes. You can print this pdf file and use as a guide to arranging the wire colors in the proper order. Getting the eight wires arranged in the proper order and pressing the eight wires FLAT between your thumb and index fingers is an important step to get the wires setup to slide into the RJ45 connector. Once the wires are FLAT and in the right order cut them so they are 1/2 inch long as shown in the photo below.


(Click for a Larger Image)

Insert the flattened wire into the the RJ45 connector as shown below:

 

   

 

Now put your RJ45 crimping tool to work. Read the directions for your tool. The drawing below shows what the crimp tool is doing. The crimp tool presses in the gold plated electrical contact down such that they pierce through insulation of all eight wire and make contact with the copper conductor. This is called insulation displacement and is why there is no need to strip the insulation off of the individual wires. The other thing the crimp tool does is press down on a hinged tab that grips onto the cables outer jacket to provide a strain relief action and helps to keep the cable and the connector intact.

       

Let's stop here for a brief moment and talk about being neat and following guidelines. Notice in the photo above how jacketed portion of the cable goes all the way up into the plug. This is right way to do this. DO NOT leave portions of the cable exposed without a jacket covering it. This jacket is key to keeping the all important twists in the CATx cable intact and to keep the pairs grouped together. 

Do NOT do this!  The long lengths of wire that do not have the pairs twisted WILL NOT carry data at 100Mbps.  Being neat is more than making it look nice. THIS WILL NOT WORK.

 

Two key rules that you NEED to follow are:

bullet    Do Not remove any more of the cables jacket than you absolutely have to.
bullet    The un-twisted part of the wires CANNOT exceed 1/2".

 

This step    which is shown above on this page is key to meeting these two rules.

 

There you have it. 

The next page will show how to terminate the CATx to a RJ45 or RJ11 jack and to a Punchdown block.

Here is a link to Dux Computer Digest where they have a very good tutorial on this subject as well:  http://duxcw.com/digest/Howto/network/cable/index.htm

The Dux Computer Digest also has some theory of twisted pair wiring if your interested:
http://duxcw.com/digest/Howto/network/cable/cable4.htm

 

 

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