Copper, of course, is obsolete in telephone and CATV backbones, as fiber's performance and cost advantages won that battle many years ago. Security concerns have also led many military and government communications and surveillance systems to convert to fiber.

For LANs used in premises networks, each Ethernet upgrade (from 10 to 100 to 1,000 megabits per second) had many users thinking only fiber optics could handle the higher speed. Each time, the copper cabling and network equipment manufacturers managed to create a new cabling solution that could meet the higher speed requirements.

Of course, each time the end-user was saddled with installing a completely new cabling system-often using only more expensive proprietary components-just to make sure everything would work together. Installing a new copper cabling system each time was always cheaper than converting to fiber optics, although this led to many companies installing five or six new copper cabling systems over a 20-year period, when one fiber network would have allowed simply upgrading the electronics at considerable cost savings.

Several factors are now changing the way users look at the copper/fiber decision. Perhaps the biggest issue is not technical; it's the requirement in the latest National Electrical Code to remove abandoned obsolete cabling as a fire hazard. Not only has that created a new and very lucrative market for contractors, but it has made users think about how long each new cable being installed is going to be useful. That they have to consider how long a cable is useful before it becomes abandoned makes them think twice about the claims of the copper-cabling suppliers.

Almost immediately after Cat 5e (the "enhanced" version of Cat 5) was introduced to handle gigabit Ethernet, manufacturers started offering an even higher performance cable, Cat 6, fully two years before it was finally approved as a new standard. Cat 6, with twice the bandwidth of Cat 5e, was called the way to "futureproof" your cabling network. Except Cat 6, unlike other category-rated cabling systems, never had a Ethernet network that required it-a "cable without a cause" so to speak.

Then Ethernet moved up another notch, from 1 gigabit per second to 10 gigabits per second, blowing both Cat 5e and Cat 6 out of the water. All the cabling for 10GbE is fiber optics, while an "augmented" Cat 6 for 10GbE is proposed but several years away.

After 20 years of successful use of one fiber design, the fiber industry responded with a new generation of multimode fiber optic cable, optimized for the higher-speed networks. Now network users planning on using 10 gigabit Ethernet in their networks can choose from two multimode fibers as well as single-mode fiber, but have no copper cabling options. Users can now choose the old standard 62.5/125 multimode fiber or a 50/125 fiber that offers better performance at a lower cost. They can also opt for a higher-performance 50/125 fiber that offers spectacular performance at a slight premium in cost. Most users install single-mode fibers and multimode fibers in the same cable to allow future upgrades to virtually infinite bandwidth.

Most of the corporate networks have already migrated to fiber optics in the backbone, connecting the computer room to the telecom closets, while virtually all are running Cat 5e from the closet to the desktop. What will it take to get fiber to the desk? Lower cost electronics are the biggest issue, but many users also complain about the lack of standardization in fiber optics. EC

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