23 August 2008

Cable Testing and Certification

Without any doubt, the first thing you do after you finish crimping your cables is to test them.
You can test them by plugging them to your NIC and see if they work, or you can use one of these LAN tester like the one I show you on the left picture.

They are easy to use, and a must have for network installers. But the one I show you is just for home usage or not intended for heavy usage.
What I mean is these LAN tester are used only to test whether you use the right color codes, to find out if there any cable cut in the middle, and some other basic things.

There are other tester type, the Tone Generator. These devices are useful if you have so many cables in your network but you didn't properly labeled them.

If you didn't label your cables properly, at some points if there's a problem on a cable you won't know which cable to check on.

What you can do is plug one end with the tone generator - the one with cables sticking out from it - this generator will send a signal through your cable.

Then you go to the other end of the cable, say, in the IDF room. There are plenty of cables there. You don't know which cable is connected to the end connected with your tone generator.

Here you grab the other tool, the one with pencil shaped and has some speaker in it. You just point the tip of the tool and when the sounds get clearer, then you know which cable you're searching for. Cool.

If you are involved in a big network project, you definitely want your hands on some more advanced testers. In a project, you are required to do cable certification on each cable you installed.
What I mean by certification is not some exam test or anything, but you must provide proof that the cables you installed are properly working without any defect.

The only tools that I can think of for cable certifications are the ones from Fluke. These tools are awesome, but they cost a fortune.

With these tools you can do any testing you can think of on a cable, you can see which wiring scheme you used on them, are there any crosstalk, if there's a cable cut in the middle you can find at what distance the cable is cut, etc.

One time I saw a cable certifier do their job. They certified on every cable we installed. One person in the IDF room and another in the work area. With the fluke plugged on each end, they can verify the cable and listen to this, they actually can talk to each other using the fluke device despite they are far apart!!!
Wow, they use the network cables as communication media, awesome.

You can generate report on each cable you tested, this report is the one you use as cable certification.
In a project you can have thousands of pages just for certifications. Usually one page represents certification for one cable you installed.

There are many parameters that you can see in a cable certification, the length of the cable, the wiring scheme, whether the cable passed the testing done by the tester, etc.
Here I show you a minimal report on a cable certification: