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Opinion: Category 7 cabling boosts throughput

Opinion: Category 7 cabling boosts throughput

As Gigabit and 10G Ethernet networks take hold in companies that need more speed, the copper physical layer of cabling has evolved to easily handle future applications. One of the most recent improvements to infrastructure is Category 7 cabling (sometimes called Class F).

The Cat 7 standard for high-bandwidth cabling was developed in Europe and is gaining increasing recognition in the U.S. It is formally referred to as international standard ISO/IEC 11801-2002.

Cat 7 cabling technology accommodates up to 600 MHz of bandwidth, the most for any type of copper cabling. Previous cabling technologies were based on conservative performance standards, such as Category 5e -- 100 MHz, and Category 6 -- 250 MHz. Early adopters of new technology such as 10G Ethernet, or companies concerned with electromagnetic interference to an environment such as a factory floor, tend to use Cat 7 cabling.

Cat 7 cabling is fully shielded -- each pair is shielded with a foil screen, and the cable itself has an overall shield. Some versions also add in a braid screen between the cable sheath and the shielded pairs. The cabling also is immune to alien crosstalk -- that is, noise from adjacent cables outside its own sheath.

Until now, Cat 5e and Cat 6 cables have used cancellation techniques to handle the effects of noise from within the cable sheath. The biggest problem to copper cable with 10G Ethernet transmission is noise from outside the sheath.

Price/performance

Cat 7 cabling is the biggest pipeline for balanced cabling. But it costs roughly three times as much as Cat 6 plenum cabling, which is priced at US$380 for a 1,000-foot reel. Companies that have a planning horizon of 10 years might be able to justify the cost of a Cat 7 installation (cable and connectors) because it should save money over alternative cabling methods that can handle applications that require much more bandwidth.

One way to look at this Cat 7 cable is to think of it like the old "Type 1" cable, but with four pairs. This cable offers the user a choice based on the style of connector installed with it (RJ-style and non-RJ-style).

With the non-RJ-style connector, it offers application sharing. With the RJ-style, the infrastructure becomes backwards compatible and interoperable.

For this cabling technology to become more mainstream, an increasing number of equipment manufacturers need to design a Cat 7 interface on their hardware. Companies also will have to grow accustomed to a different interface. And the cabling has a larger diameter than Cat 6 because it's double shielded and typically uses a 23 American Wire Gauge bare copper conductor (vs. 24 AWG for Cat 6, 5e, 5 and others).

In addition to pricing this class of cable and connector, certification by a National Research Test Lab is important. This means the lab's mark will appear on the cable jacket. The mark shows that the equipment has been tested by a nationally approved test lab for safety and performance and that it complies with the international Cat 7 standard's performance specifications.

A Cat 7 product lends itself to new bandwidth, access, storage and speed demands. Depending on your needs and future goals, a cost-benefit analysis that compares this latest copper cable technology with its competition's performance can help determine what to use.

Michelson is president of Business Communication Services, which publishes BCS Standards Updates covering copper, fiber, coax, and wireless media. She can be reached at randm@volcano.net.


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