Cat 5e & Cat 6 Overview
Category 5e
Category 5 Enhanced, like Category 5 is a 100MHz classification. However, the performance requirements of a Category 5 Enhanced system are more stringent.
This is achieved by improving the Attenuation to Crosstalk Ratio (ACR) by reducing the NEXT levels both in the cables and connecting hardware. Further testing is also carried out to ensure emerging technologies will also be supported.
With the introduction of Gigabit Ethernet, which utilises all four pairs in a data cable, it is now necessary to test the total crosstalk that could be present within the cables. Gigabit Ethernet, 1000Mbits, splits the signal into four equal amounts for transmission. The protocol also allows transmit and receive at the same which also causes problems. As a result, it is necessary to test the noise transmitted on any three pairs to the fourth for all four pairs which is known as Power Sum. This test is carried out for ACR and NEXT.
This cabling system will provide future proofing for the Gigabit Ethernet protocol and any future protocol's which are supported by 100MHz of bandwidth. Currently Gigabit Ethernet is a protocol commonly used in backbone cabling but will theoretically be commonplace to the desktop in approximately three years. This cabling system will support full migration currently up to Gigabit Ethernet to the desk.
Category 6
Unlike earlier standards, Category 6 or Class E is a 200/250MHz classification. The two frequencies are specified with a positive Power Sum ACR at 200MHz, more signal than noise, and a negative PSACR at 250MHz, more noise than signal. The upper limit has been set due to the Active hardware manufacturers ability to extract a small signal from a larger noise.
There are additional tests carried out above Cat5e which include equal Level far end Crosstalk, ELFEXT, and the Power Sum of this measurement, PSELFEXT. This is due to the transmit and receive in both directions of the protocol causing problems with far end crosstalk being transmitted to the near end.
This cabling system will provide future proofing for the Gigabit Ethernet protocol and any future protocol's which are supported by 200/250MHz of bandwidth. This will give true future proofing for standards over and above Gigabit Ethernet, the 10Gbit/s protocol is currently being designed. This cabling system will support full migration to Gigabit Ethernet and beyond to the desk.
|
