But you can't buy a Cat 5e tester

I read with interest your recent editorial, "Getting testy about testing" (April 2003, page 7). You have fallen into an assumption that many do...

I read with interest your recent editorial, "Getting testy about testing" (April 2003, page 7). You have fallen into an assumption that many do, and you may modify your perspective after reading what I have to say.

Your premise is based on the fact that many contractors have Cat 5e testers they use, but when they come across a Cat 6 job, they can't test it to Cat 6 requirements, so sometimes only test them to Cat 5e.

Did you know that it is impossible to buy a Cat 5e tester? No manufacturer makes one. You can buy (obsolete) Cat 5 testers that cannot measure ELFEXT—the measurement was invented after the products were. Or, you can buy a Category 6 tester. But no supplier provides a Cat 5e tester. The hardware costs to make the Cat 5e measurements at high speed are the big obstacle. Making the same measurements at 250 MHz versus 100 MHz does not add that much cost, mostly design care in the RF section.

What you will find are people who are clinging to their old Cat 5 testers, and passing off Cat 5 certification results (wiremap, length, insertion loss, and NEXT) on Cat 5e links that should also be tested for PSNEXT, return loss, ELFEXT, PSELFEXT, delay, and skew. That's a bigger problem, in our experience. The "e" in Cat 5e is very significant as far as cable qualification is concerned.

Mark Johnston, RCDD
Strategic Alliance and Planning Manager, Fluke Networks

Mr. Johnston is right; I have modified my perspective, thanks to his clarification. The thought that some supposed Cat 5e systems are really certified only to Cat 5 makes me even more cranky than I was when I wrote the April editorial.—Ed.

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