Cabling Standards ... Then and Now

Author: Mark Atwood

June 2008

Over the years, bandwidth demands have created a need for better cabling systems. It is hard to believe that it has been only 17 years since the first cabling standard (568) for Unshielded Twisted Pair Cable (UTP) was released by the Telecommunications Industry Association (TIA). It still feels like last year that we were installing IBM Type 1 connectors, or Thinnet couplers, or my personal favorite Thicknet vampire taps.

The copper cabling standards have come a long way since then and TIA has worked closely with IEEE to ensure that the cabling systems meet the application demands of the users. Category 3 was the first cabling system developed for data transmission in the late 1980’s and had a bandwidth of 16 MHz. This standard is no longer recognized for data transmission and is used exclusively for voice applications. Category 4 had a bandwidth of 20 MHz, but only had a lifespan of about 18 months and is no longer recognized by the standards. This short life was brought about due to the release of the Category 5 standard in 1991. This system had a bandwidth of 100 MHz, a huge upgrade in performance without a major upgrade in cost. Category 5 is no longer recognized by TIA.

In the mid 1990’s, Gigabit Ethernet was being developed by IEEE and TIA determined that the standards for Category 5 were not high enough to consistently handle the demands for Gigabit Ethernet. This led to the development of the Category 5E standard, which was eventually released in 2000. This was still a 100 MHz solution, but had an upgrade in the cable and connectivity to allow for more headroom. In 2002, Category 6 was adopted as a standard. This 250 MHz solution allowed for increased bandwidth levels over the standards (headroom) for Gigabit Ethernet and future applications. This is the cabling system most widely installed today for data applications.

A new standard was released in April by TIA. This standard is called Category 6A, or Augmented Category 6. This standard will have a bandwidth of 600 MHz and was developed specifically for 10 Gigabit Ethernet. The products for this standard are already available and being installed mostly in data centers. Some manufacturers have an unshielded solution, while others have a screened solution. The performance for both types is identical. While this standard will give you plenty of headroom on your existing applications and a longer lifespan, it also has an increased cost over Category 6.

While copper has gone through their constant upgrades over the years, so has fiber optics. Multimode Fiber (MM) is the most widely used solution in the horizontal and data center environments. In the mid 1990’s, 62.5/125 MM fiber was the most commonly installed fiber across the country. This fiber was powered by LED’s and was great for 100Base-T applications. When Gigabit Ethernet was developed, LED’s could not flash fast enough to operate this application. Lasers needed to be used and 62.5/125 MM fiber was not the ideal fiber for lasers.

This led to the migration to 50/125 MM fiber, which was better suited for laser applications. 50/125 MM fiber is not unlike copper in that it has been constantly upgraded over the years and the most widely installed solution is the Laser-Optimized fiber, which allows for up to 10 Gigabit Ethernet applications for up to 500 Meters. IEEE is now developing 40 Gigabit Ethernet and 100 Gigabit Ethernet to run on these fibers, but they will not be available for several years. Single-mode fiber is also an option for your networks. The bandwidth they can carry and distances they can travel greatly surpass multimode fiber, but there is also a significant increase in cost due to the electronics involved to run these applications.

The magic question is, “Which solution is best for my cabling infrastructure and data center?” The lifespan of a cabling system should be at least 10 years. Several factors need to be addressed when deciding on your cabling system such as your current and future applications, the length of time you will be in your current facility, hiring a qualified contractor, as well as your budget. Proper research will allow you to have the best cabling system for your offices, laboratories, manufacturing plants, warehouses, and data centers.