Getting testy about testing

The idea was that if you included fiber in the installation, it would be there when you need it.

Two issues related to the testing of horizontal cabling systems have been bugging me lately. In one case, the frustration comes from the failure to use available technology, while in the other, the frustration comes from the lack of a certain type of technology.

First, please follow this scenario. A cabling contractor has been carrying out projects that almost exclusively specify Category 5e cabling to the desktop. When this contractor wins his first Category 6 job (I'll be a chauvinist and use male-gender terminology for the sake of simplicity), he has the knowledge and skills to successfully install a Category 6 cabling system. But one thing he doesn't have is the proper equipment to properly certify the installation to the TIA's Category 6 specifications. And because he got the job by low-bidding to the point where he's not really making much profit on it—his goal is to sufficiently impress the customer and earn ongoing moves, adds, changes (MAC) work—it's not exactly in the budget to invest in a Category 6 tester with a price tag somewhere in the mid-four-figure range.

What does the contractor do? Let's hope that every single contractor in this situation will choose to rent the necessary tester. Equipment rentals are available for situations exactly like this one. In fact, it is probably a wise choice for a contractor to wait until a certain percentage of work is Category 6-based before investing in a tester capable of that level of certification. But something tells me that in this situation, perhaps only 99.99% of contractors choose to rent. That other tiny percentage of the population just certifies the system to the highest level achievable by the testers they own. And if that's the case, then somewhere out there, there are one or maybe two installed systems with Category 6 cable and connecting hardware that are certified only to Category 5e specifications.

How can this situation be allowed to happen? If the end-user customer allows it, that's how. The onus here is on the end user to first draft a scope of work that includes not only installing, but also certifying the cabling system to the Category 6 specs. It would be prudent to include language in the specifications to ensure that a Category 6-capable tester is used. Then, when the job is completed, don't simply accept the certification documentation from the contractor, file it away, and hope you never have to look at it again. Invest a small but vital amount of time to make sure that the system was, in fact, tested to 250 MHz like the TIA specifications dictate.

Issue number two has actually been in my craw for a little while now. Maybe there's a simple answer and I just haven't asked the right questions yet. But it seems to me there are a number of end users who many years ago took someone's advice and had 62.5/125-µm multimode fiber installed in their horizontal systems and left inactive. The idea was that if you included fiber in the installation, it would be there when you need it. And at the time, fiber's information-carrying capacity was thought by many to be limitless.

Then, in the late 1990s, it became evident that the information-carrying capacity of 62.5/125-µm fiber was, in fact, limited. Testing done when Gigabit Ethernet was being developed showed that not all multimode fibers performed equally.

Back to present-day, many of the users with installed fiber still have not used it. But now they're wondering just what its capabilities are. What is its bandwidth? I don't know. How can anyone find out its bandwidth? I don't know. That's why it's bugging me. At one point, I was told that test equipment does exist that can determine a fiber's bandwidth. But it's not exactly portable, and its price rivals that of a waterfront property.

So, there they are. Two testing issues that have had me wondering lately. As always, I welcome all relevant facts and opinions about them.

Patrick McLaughlin
Chief Editor
patrick@pennwell.com

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