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The Scary Post-Cat. 5 World

Feb. 1, 2003
As the industry continues to struggle with a Cat. 6 standard, you're stuck choosing between obsolete (Cat. 5), problematic (Cat. 6), and unconventional

As the industry continues to struggle with a Cat. 6 standard, you're stuck choosing between obsolete (Cat. 5), problematic (Cat. 6), and unconventional (Cat. 7) technologies.

Now that Cat. 5 cabling is yesterday's news, everyone wants to know where the industry is heading. The Cat. 5 years were a relatively stable period in the data-cabling business. Although testers were expensive, installation techniques difficult, and testing doubly troublesome, it was certainly possible to know and meet the requirements placed upon us. Unfortunately, the post-Cat. 5 world doesn't look so stable. In fact, it's starting to look like the bad old days of data cabling-when there were lots of different cabling methods (none of which were compatible). In reality, it probably won't end up being that bad, but you can be sure the relatively calm years of Cat. 5 cable are officially over. Here are some things to look out for in the future.

Standard? What standard? Forget about an official Cat. 6 standard in the next few months; and don't get your hopes too high for it later this year, either. Sure, it's possible a standard could materialize soon, but don't bet on it. And even if it does, I'm sure it will require extensive revisions.

At a recent trade show, one large manufacturer told me it doesn't expect an approved Cat. 6 standard until 2001. So, at least for now, there really is no such thing as Cat. 6 cabling as far as standards go. However, there is a draft standard (recognizing two different types of Cat. 6 cable) and a lot of debate among manufacturers. A number of manufacturers want to loosen the standard so they can meet it more easily. There's also a lot of dissension over connector types; right now it looks like the Cat. 6 connector will be similar to an RJ45, but not exactly the same.

One problem is that manufacturers want to make their Cat. 6 products "backward compatible" with Cat. 5. That is, they don't want to let go of the RJ45. Why is this a problem? As convenient as the RJ45 is, it's a small module and the source of a lot of circuit problems. A larger module (such as one planned for Cat. 7 cabling) would perform much better.

Until then, proprietary systems abound. Before the advent of structured cabling, the various cabling systems (AT&T, IBM, Northern Telecom, Digital, etc.) were incompatible. Until a solid Cat. 6 standard arrives, we're almost back to that same situation. When manufacturers' materials aren't compatible, workload increases at almost every level of operation. On the job, you'll have to make sure you're installing the right brands. By the way, your overhead just went up.

Tester trauma. Okay, first you incur the cost-$5,000 or more for a Cat. 6 tester. And remember: These testers are built to meet a draft standard, not an official standard. So, when the real standard comes out, you may have to modify or replace the tester. Tester manufacturers make their products for a standard bandwidth (signal rate) of 250 MHz, but cable manufacturers make theirs for 200 MHz. Where will it end up?

One of the dozen or so tests that will be required for Cat. 6 cabling is the PSELFEXT test (Power Sum Equal Level Far End Crosstalk). Sure, the Cat. 6 testers will perform these types of tests automatically, but your installers will still have to interpret, report on and understand them. This translates into additional training for everyone.

More pressure on the installer. Earlier, I mentioned manufacturers want to get the standard loosened. That means they want to eliminate any margin built into the standard. In electricianese, "margin" translates to "slop factor." When I asked one manufacturer how it would prevent problems, the representative got serious and said, "We'll really have to make sure the installers are a lot more careful." That means limiting your installers to only 25 lbs of pulling tension, and 1/2 in. of untwisting pairs will no longer be good enough. It also means when problems develop, you'll be the first person customers blame. Feeling uncomfortable yet?

Cat. 7 cabling. Cat. 7 should be on the market now. This stuff could work in real-life applications. The industry people I've talked to expect Cat. 6 to be short-lived and for the industry to regroup around Cat. 7. The number of jobs and customers that will end up as Cat. 6's road kill is hard to tell, but it looks like it may turn ugly.

The cost of installing Cat. 7 cabling will probably end up being greater than the cost of the same installation with fiber (it's already about equal).

What about fiber? Fiber has a lot of things going for it. First of all, you don't have to replace it every three years. Secondly, it's as cheap, or cheaper, to install than Cat. 6, and easier to test. Thirdly, there's no reason for a distance limit in most fiber installations. You should base fiber networks on "collapsed backbone" architecture, with fiber runs going from the wall outlet directly to a main distribution frame.

However, it seems fiber manufacturers have a habit of snatching defeat from the jaws of victory. Right now, the fiber world is involved in connector wars. The standards call for the SC connector, which is too large and overpriced for most installations. No standard covers the "small form-factor" (SFF) connectors, but everyone uses them.

The extra expense in fiber installations relates to opto-electronics. Fiber hubs are more expensive than copper equipment. This is why the collapsed backbone architecture is so attractive-you eliminate all or most of the hubs and patch panels. Yes, prices continue to drop, but it will still be a little while before these products come with an equal price tag. Is this extra cost (5% to 15% overall, not counting the savings of using a collapsed backbone design) enough to justify the use of copper cabling? I don't think so.

What's the bottom line? First of all, if you want to install Cat. 6, go into the task with your eyes wide open. Make sure your customers know there are problems with the technology and that a standard doesn't even exist. Cover your risks, and don't leave yourself as the person who gets blamed when something goes wrong.

Although it would be nice if we could wait for Cat. 7, that doesn't look like a possibility. Europe will almost certainly have Cat. 7 technology before we do. However, even that's a year or two away. So, like it or not, for the next few years you're stuck choosing between Cat. 5 (obsolete, too slow), Cat. 6 (a problematic technology), and optical fiber (a superior technology, but one that never seems to win over customers).

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