An Article about Cat 7 Cabling Systems

The hunger of IT networks for bandwidth continues to increase. Against the background of mushrooming requirements, the international standardization bodies are working on a new and trail-blazing generation of cabling systems. Class F and Category 7 cabling systems with a bandwidth of 1,000 MHz are the state of the art in terms of standardization.

Ethernet is the dominant communication technology. Its scalability is allowing it to penetrate into all high-end fields of application. Since the introduction of Ethernet, the data rate has been multiplied by the factor 10 about every 6 years.

In spite of the explosive development of data rates, physical networks were able to stand up to this pressure for a long time thanks to improvements in electronic transmission and signal processing methods.

However, the introduction of 10 Gigabit Ethernet means that, for the first time, a technology is available which can no longer be transported by a large part of the networks installed worldwide. This is why Class EA (500 MHz) / Class F (600 MHz) cabling systems are now being installed for the transmission of 10 GigaBit Ethernet.

If we assume that data rates will be multiplied by 10 again in the course of the next 6 years, the network infrastructures will be faced with transmission rates of 100 GigaBit/sec by 2012 at the latest. Besides the transmission of TV signals, this is one more reason to invest in a new Class F / Category 7 cabling.

The requirements for the new Class F / Category 7 are defined in working group 3 of ISO/IEC JTC1 SC25 and result in Amendment 1 to ISO/IEC 11801. With the help of a mathematical model, the complex interaction between channel requirements, permanent link and components was examined and the first draft standards for Amendment 1 to ISO/IEC 11801 generated. Category 7 plugs are to be found under IEC 60603-7-71 and IEC 61076-104. Category 7 cables are to be found under IEC 61156-5/6.

The main difference between the new F cabling class and the existing E and F classes is the bandwidth, which has been increased from 500 MHz and 600 MHz respectively to 1.000 MHz. The results are more stringent requirements with regard to NEXT and attenuation as well as improved values for the attenuation of Alien Crosstalk.

The great superiority of the new F cabling class can best be demonstrated via the ACR (the difference between NEXT and attenuation). At 500 MHz, Class E already has a negative ACR of -21.4 dB whereas Class FA is still positive at an ACR of +6.9 dB. Class FA is therefore 28.3 dB better (a factor of 26).

The values described in the following apply for the attenuation of Alien Crosstalk. A distinction is made between alien near-end crosstalk (PS ANEXT) and alien far-end crosstalk (PS AACR-F).

In the case of shielded cabling systems, the Alien Crosstalk requirements are considered as fulfilled if the specifications for the coupling attenuation are complied with even in the laboratory. The coupling attenuation evaluates the overall EMC behavior of a cable or individual link. The coupling attenuation consists of the shield attenuation and the asymmetrical attenuation taken together. It thus defines the degree of reduction of electrical influences on a signal path:

In this connection, experts from the international standardization bodies were able to prove theoretically and via technical measurements that the following additional statement can be made about shielded copper cabling: If the coupling attenuation for Class E and F links is 10.0 dB or (for Class FA links) 25.0 dB better, the values for the parameters Power Sum Alien NEXT (PS ANEXT) and Power Sum Alien ACR-F (PS AACR-F) are complied with automatically as a result of the design, making it unnecessary to demonstrate them explicitly. Or, expressed as formulae: Coupling attenuation for Class E and F: > 90 – 20 log(f), > 50 dB up to 100 MHz Coupling attenuation for Class F: > 105 – 20 log(f), > 65 dB up to 100 MHz Due to the coupling mechanisms, this connection only applies for shielded cablings and not for unshielded ones. In contrast to shielded cabling systems validated in this way, it is not necessary to carry out field measurements of the Alien Crosstalk.

The inclusion of 10 GBE and more via 100 m copper is of great technical and economic importance for the dimensioning of networks with a secure future. The previous Class D/Category 5 and Class E/Category 6 cablings are not suitable for this task. This is why the current minimum equipment of a structured cabling is based on the requirements of Class E (500 MHz) or Class F (600 MHz). Some are already casting their minds forward to the technological leap due to take place in the next few years. Tests have shown that transmission performances exceeding 50 GigaBit/sec via Class F / Category 7 are not a dream. In the field of home cabling according to ISO/IEC 15018 & EN 50173-4, cabling class FA is already being used for multimedia services up to 1,000 MHz. The use of high-value data cables according to Class F / Category 7, ideally in AWG 22 (for example MegaLine F10-130) and in conjunction with the necessary connector technology (for instance MegaLineNet) is a reliable guarantee

Cat 7 Cabling Systems Manufactured by Leoni Kerpen GmbH Zweifaller Str. 275 - 287 52224 Stolberg Germany Tel. +49 (0)240217-359 Fax +49 (0)240217-360 Mobil +49 (0)172- 2422078





Tag : Structured Cabling - Cat 7 - Category 7 - Class F Cabling.