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Note: The following technical article was current at the time it was published. However, due to changing technologies and standards updates, some of the information contained in this article may no longer be accurate or up to date.

Leading the Industry to Category 7 and Class F

Siemonā€˜s SYSTEM 7® including the TERA™ connector delivers performance to 1 GHz.

Q. What are the benefits of category 7 technology?

The pending standards for category 7* components and class F links and channels will offer unsurpassed bandwidth over twisted-pair cabling. A Siemon SYSTEM 7® solution using the TERA™ connector delivers excellent results to 1 GHz - well beyond the 600 MHz upper frequency limit of the current draft specifications. This capability allows demanding applications like broadband video, with an upper frequency requirement of 862 MHz, to operate over class F cabling with simultaneous connections to other networking applications. For example, a single class F channel can support connections to such diverse applications as analog voice (1-pair), a high speed LAN (2-pair) and broadband video (1-pair).

This technology supports all applications designed to operate over twisted-pair cabling, as well as those that might otherwise require fiber or coax. The noise immunity and emissions performance of class F support the most advanced LAN applications without expensive electronics needed to implement complex encoding or signal processing.

The pending category 7 and class F standards will enable shielded cable installations to perform to their full potential in terms of bandwidth, versatility and ease-of-use. Category 7 cables will be "fully shielded", with individually screened twisted-pairs and an overall shield. This type of cable is dominant in several European countries. However, its global acceptance has been impaired by connecting components that are limited in terms of performance, ease of use, adaptability, and size. A category 7 interface that is specifically designed for fully shielded cables will overcome these connectivity issues. The TERA™ connectors consistently deliver high performance margins and linear frequency response up to at least 1 GHz, with minimal termination time, and in the same space as an eight position modular (or "RJ") style connector.

Q. Why not just go to fiber instead of category 7?

When compared to the overall cost of a fiber LAN, a category 7 solution provides exceptional performance and bandwidth at a fraction of the cost of fiber. The Siemon Company conducted a cost study comparing a 24 channel SYSTEM 7® installation to a 62.5/125 multimode fiber system. While the installed cost of the two systems is comparable, the active equipment for a fiber LAN is approximately 6 times the cost of copper equipment. When the complete cost of a LAN installation is considered, SYSTEM 7® provides a high bandwidth solution for less than half the cost of multimode fiber.

In addition to the cost advantages, category 7/ class F offers functionality not available with fiber. Since each individual pair is shielded, class F (category 7) channels essentially eliminate crosstalk noise between pairs. This allows System 7 to support multiple applications over one cable. At the work area or telecommunications closet, the TERA connector's capability of 1,2 & 4 pair plug modularity enables direct access to multiple equipment ports and applications in the same outlet.

Q. What are the differences between category 6 and category 7 technology?

Category 6/class E delivers the highest level of transmission performance available without individually screened pairs. For the vast majority of business and institutional applications, 250 MHz bandwidth is more than adequate for the life of the cabling system, making category 6/class E the perfect choice for generic premises cabling.

The goal for category 7/class F is to be as good or better than any other type of balanced media for each transmission parameter. For example, the channel will deliver positive power sum ACR up to at least 600 MHz.

There are significant physical differences between category 6 and category 7 components. The "fully shielded" construction of category 7 cable results in a larger outside diameter and less flexibility than UTP or ScTP. These attributes require greater care in the design of pathways and termination spaces to allow for more space and larger bend radii.

Another difference is with the connecting hardware. The pending category 7 specification requires connectors to provide at least 60 dB of crosstalk isolation between all pairs at 600 MHz. This requirement is 32 dB more severe than category 5 at 100 MHz, and 20 dB more severe than category 6 at 250 MHz.

Click to enlarge

Click to enlarge

NEXT Performance - Siemon SYSTEM 7® Four Connector channel (100 m) with 1 meter cross-connect

Q. What types of businesses and applications would benefit from using the new TERA™ connector and System 7 (class F) cabling?

Because fully shielded cables are used with System 7 cabling, we envision it as filling market demand in areas where fully shielded and screened cabling is the dominant twisted-pair media, such as in parts of Europe and Asia. Regardless of market bias, fully shielded solutions are applicable in environments with significant ambient noise, such as broadcast stations. Other environments where shielding is appropriate are those where radiated emissions must be minimized for security purposes (e.g., Tempest).

Businesses that may benefit from category 7/class F include technology leaders that need the performance edge to gain a competitive advantage in the market place. These may include financial, insurance, and other information-intensive enterprises. Educational and certain government institutions that have traditionally been at the technological forefront may also adopt category 7/class F technology.

Yet another potential market for class F is for command, control and communications systems within residential and commercial buildings. The ability of a single cable type to serve all copper cabling requirements including coax, without shared sheath restrictions provides benefits in terms of both performance and cost.

Q. What makes the technology so innovative?

Breaking free from the eight position modular or "RJ" style interface paved the way for many of the TERA™'s innovations, like its unparalleled performance and 4-, 2-, 1-pair modularity. Freedom from the constraints of the "RJ" connector allowed Siemon to create a new interface with pair-to-pair isolation, compactness, reliability, and installation ease as primary objectives.

Beside the general benefits of category 7, the TERA™ has the advantages of a best-of-class termination process and compact size. It fits into the same standard IEC panel opening as "keystone" style outlets - the same opening dimensions used for existing Siemon MAX faceplates and patch panels. Compact size and backward compatible mounting accessories allow the TERA™ connector to be installed with commercially available patch panels and faceplates anywhere in the world.

In addition to its performance, ease of termination, small size, and compatibility with existing mounting components, the TERA™ includes other features specifically intended to provide flexibility and customer acceptance. The TERA™ outlet is capable of mating with a single 4-pair plug or a combination of 2-pair and 1-pair* plugs to support multiple equipment connections on each end. They are side stackable, allowing for the same density as UTP or ScTP, and can be snapped in from either the front or rear of the panel opening.

The same features that are available with our other outlet designs such as a color-coded icon tab and door are also provided. The plug features a snag-free design, color-coding as well as a robust and intuitive latch mechanism.

An innovative cable preparation tool and bonding system also contribute to positive installer acceptance of the TERA™ and System 7.

Q. How is Siemon positioned in the development of this technology?

The Siemon Company has taken a leadership role in category 7 development, and is actively involved in the ISO/IEC category 7/class F standardization.

Within these organizations, meetings have been held since 1997 to define the category 7/class F performance requirements and to select a standard connecting interface. Eight connector interfaces have been proposed. Two are "RJ" style. The other six are non-"RJ" style.

In January 1999, the ISO technical committee decided to select one RJ and one non-RJ proposal for further consideration. The actual selection will take place at the committee's next meeting in June 1999.

The Siemon Company decided to develop a new connector interface for System 7 because of our desire to reach beyond the limitations of an "RJ" style interface. Our goal is to develop a twisted-pair connector that offers the highest possible bandwidth - well beyond 600 MHz. Furthermore, unrestricted shared sheath capability is a significant benefit of category 7/class F which can be fully exploited using the 2- and 1- pair modularity of the TERA™ and System 7.

*At the time of printing this magazine, category 7/class F specifications were under review by ISO/IEC.

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