Jim Hayes

Fiber Optics Columnist and Freelance Writer

HAYES is a VDV writer and trainer and the president of The Fiber Optic Association. Find him at www.JimHayes.com.

Articles by Jim Hayes

October 2011
In fiber optics, there has been a lot of discussion about encircled flux (EF), much of it more confusing than clarifying. EF is simply a new way of looking at an old, well-known problem, defining mode control for multimode (MM) fiber testing. READ MORE
September 2011
A couple of years ago, several fiber manufacturers introduced optical fibers that were much less sensitive to bending. Normally, bending or stressing an optical fiber causes loss. In normal use, optical fibers had to be handled carefully and not be subjected to tight bends, kinks or pinching, which is a problem around patch panels and transmission equipment. READ MORE
August 2011
Recently, I read several articles about premises cabling in which the authors called unshielded twisted-pair (UTP) cabling “Cat 5,” even though, over the last 20 years, we’ve seen UTP developed into enhanced Category 5 (Cat 5e), Cat 6, augmented Cat 6 (Cat 6a) and even the (maybe) future standard for Cat 7. READ MORE
August 2011
Fiber optic advocates used to point to the copper types and snicker. They’d note that, while copper cabling went through eight or nine generations of coaxial and unshielded twisted-pair (UTP) cables, one fiber would have sufficed. But then along came gigabit Ethernet, then 10-, 40- and 100-gigabit networks. READ MORE
July 2011
Contractors who do fiber optic projects should be familiar with most of the usual applications, such as telecom, cable television, local area networks and closed-circuit television (CCTV), but may not have much experience with the more unusual or newer applications. READ MORE
July 2011
Two different instruments that are often described as “works like radar” can test copper and fiber cabling. For copper, it is a time-domain reflectometer (TDR). For fiber, it is an optical time-domain reflectometer (OTDR). These instruments are alike in some ways but different in others and are equally tricky to use. How well do you know these gadgets? Answers and explanations are in red. 1. READ MORE
June 2011
Last month, I mentioned the poor quality of some fiber optic patchcords I tested. This month, I examine the subject of cable quality, both fiber and copper. The old saying goes, “a chain is only as stong as its weakest link,” and that is especially true for cabling. A well-installed cable plant that passes all performance and/or certification tests can be undone by faulty patchcords. READ MORE
June 2011
We questioned your knowledge of cabling testers last month, so now let’s see how well you know how to troubleshoot problems with those testers. Correct answers and explanations are in red. 1. If a copper certification tester fails an unshielded twisted-pair (UTP) cable, what is the most likely problem? A. Cable is too long B. Too much attenuation C. Alien crosstalkD. READ MORE
May 2011
The entire performance of a fiber optic (or copper) network depends on the performance of the patchcords used for interconnects and for connecting communications equipment, but it’s easy to take patchcords for granted. They are inexpensive, often not tested properly, and sometimes treated poorly. READ MORE