It is time to put some pressure on the testing manufacturers to provide us with "worst case" specifications.
December 1, 2001
I don’t know about you, but I am finding it increasingly difficult to compare all of the proposed Category 6 systems out there. Like many people, I prefer to compare channel specifications, as opposed to specifications for individual components. In this regard, it can be quite difficult for consumers to compare “apples-to-apples”, as each manufacturer presents its respective test results in a different fashion. Some provide best case 4-connectors results; others provide worst case 2-connector values. And other manufacturers provide average 2 or 4-connector values.
On top of all of that, how are we able to confirm that we have achieved the published specifications if the Pass/Fail of the field test instruments are set at the minimum acceptable level?
I would like to suggest that we, as consumers, begin to put pressure on the manufacturers to provide us with the “worst case” specifications in a 4-connector model. This would represent that absolute worst-case scenario we find out in the field (i.e., installations with consolidation points and multi-user telecommunications outlet assemblies). Were this to occur, it would make it easier for us to compare each of the respective systems and determine if the price difference is of any true value.
As for field testing, we should take it upon ourselves and test the installed channel against the worst-case values provided by the manufacturer — setting the Pass/Fail limits higher than the standards. In discussing this approach with various manufacturers, there appears to be some reluctance to embrace this level of testing. I am not sure that I completely understand why. I would like to think that any manufacturer positioning its products well beyond the standards would be prepared to stand behind its claims.
Let’s say that we purchase the best proposed Category 6 cabling system, one that is supposed to have performance values well beyond those specified in the proposed standards document. Even with this system, testing to the proposed standards limits does not ensure that we have achieved the superior specifications once the system has been installed and terminated.
Some argue that if you want to verify the results, you can sift through each test result and see what each value was. Isn’t there a more time-efficient method in this day in age? The answer is “yes”, there actually is a more effective method: setting the field test instrument Pass/Fail limits based upon the purchased cabling systems values and testing accordingly. This can be carried out on some testers more easily than on others. The easiest way is to set the values on a flash card and give the card to the contractor to insert into the tester, thereby “locking-in” all test parameters.
I can already hear the cabling manufacturers screaming: “This isn’t a fair test.” To this protest, I would reply: “Why not? Don’t your published results represent worst-case? If they do, what is the problem?”
Let’s remember that the purpose of field testing is not only to validate the manufacturers’ claims, but also to validate the workmanship of the installer.
If the superior cabling system we talked about is tested to the standards limits and barely passes, we would likely be annoyed that the premium we paid was lost due to improper installation techniques or inaccurate manufacturer claims.
Once we actually have the test results, what are we to do with them? Like most people, we file them. Actually, the tester manufacturers tell me that few people actually know how to read the results. With this in mind, most people tend to look for the Pass/Fail result, as opposed to a lot of numbers.
Some testers have software that allows you to plot the test results in a graphical format. What I like about this format is that I can see how the channel under test performed, in addition to the performance trends. Some testing software even allows you to re-run the test results and compare them to customized limits. However, in order to perform these “what if” test scenarios, all test points for each channel test must be saved. This can also be specified in the flash card given to the contractor.
At the end of the day, let’s remember that manufacturers, suppliers, contractors, consultants and consumers are all trying to do their jobs and make a living. I don’t know about you, but since the events of September 11th, I find myself softening my opinions and views (if that’s possible) and looking for ways to work out deals that are fair to everyone.CS
Mark B. Maloney, RCDD, is a Senior Consultant with Ehvert Technology Services in Toronto and a member of Cabling Systems’ Editorial Advisory Board.