Testing Extended Length Vendor-Specified Channels

By choosing a standards compliant cabling system you can be assured that your cabling will always support any application designed to be used with that class/category of cabling. The network equipment designers use the performance requirements of those categories to design and evaluate their equipment and that equipment may be unable to perform as expected if the cabling does not meet those requirements.

But these standards contain worst case requirements which means that whilst compliance with the cabling standards assures application support 100% of the time, it is still possible for the application to function when the performance of the cabling is at a level which does not meet the requirements of the standard.

We understand the pressure to connect a device beyond the guidance of the cabling standards (“just a little further”!), so if you choose to deploy an extended-reach channel, first understand that the installation will not be standards compliant. This may mean that the application support will be limited to certain data rates, certain cables and components, certain installation conditions, or is tied to certain types of network equipment. It could also mean that the application support may not be assured by the network equipment manufacturer, and instead falls to the cabling vendor. That might be just fine with your customer, but it’s best to make sure. You may just need to educate them about the solution and the implications of non-standards compliant cabling.

And just because something isn’t standards compliant, doesn’t mean you don’t have to test it. Because extended-length channels are not standards compliant, these vendors provide specific warranties regarding the conditions under which they provide application support and requirements to which the cabling must comply in order to issue that warranty.

If anything, testing is even more important when attempting to get a little extra performance out of the cabling—even if the cable is verified and approved by a vendor for longer-distance runs. If you don’t test to their spec and it ultimately doesn’t work, you’re liable and on the hook for the rework.

Fluke has added a number of vendor-specified limits to our DSX CableAnalyzer series of copper cable certifiers for easy pass/fail testing of their extended-reach channels —all you need to do is select these test limits on your tester. Get the latest Versiv Limit Lines document and click on "Vendor" in the index on page 1 to jump to that section.

By far the easiest way to ensure application support, interoperability and equipment changes is to use standards based lengths and limits. However if you or your customer intends to consider extended length channels, then Fluke recommends the best option is to work with your cabling vendors to understand their guidelines, limitations and warranties for extended length channels, and to use their specific extended-distance limits in our DSX tester for easy pass/fail testing.

Reach out to us for more information, or have your vendor contact us.