Analysis on Structure and transmission performance of cat6 Cables

Cat6/Class E has been releasing international standards for copper cabling systems for nearly three years. In the market, solutions represented by Cat6 systems have become the representatives of the mid-to-high-end cabling market. While the six types of systems are widely known and accepted, there is always a misunderstanding about the structure of the six types of cables: Only cables with cross isolation are the characteristics of the standard six types of cables. What is the real answer to this question?

First, let's look at the relevant international standards that are strictly defined for the six types of systems. In the latest version of ISO/IEC 11801: 2002, the core content of Class E system is defined as "Class E is specified up to 250MHz ", A series of Cable Transmission Performance indicators are defined around this requirement, including Return Loss, Insertion Loss, NEXT, ps next, ACR, ps acr, ELFEXT, ps elfext, Propagation delay, and Delay skew. The specific requirements of cables mainly involve impedance, current, voltage, and power parameters. There is no specific requirement on isolation in this article. In another important international standard TIA/EIA568B.2-1 for integrated cabling, Cat6 is defined as "Category 6: This designation applies to 100 & #8486; & #61472; cables whose transmission characteristics are specified up to 250 MHz ", and a series of electrical parameters are defined, which are basically the same as those specified in ISO/IEC 11801. Therefore, any 4-to 8-core twisted pair copper cable system that meets the electrical parameters specified in the above standards will be a qualified Cat6/Class E-level system.

So how is the so-called cross isolation and one-word isolation cable born? What is the difference between them?

As we all know, before the appearance of cat6 systems, the transmission performance of the traditional four-to-eight-core copper system can only meet the five-class or cat5e standards, and the system transmission bandwidth can only reach 100 MHz, therefore, the new cat6 system requires more bandwidth than 150% of the traditional cat5e/cat5e system. In order to meet this new requirement, a large number of electrical parameters not previously specified in the era of five types of systems have been added in the design of copper cable systems. If we classify these parameters based on their importance, we will find that all kinds of crosstalk parameters have the greatest impact on the digital transmission process, including near-end crosstalk, power accumulation near-end string winding, remote crosstalk, etc. The main cause of this crosstalk is the interference between the telecom numbers transmitted on different lines in an outer skin. The focal point of crosstalk is the connection between cables, modules, and distribution frames. This type of crosstalk changes with the line-to-space location and transmission frequency. In order to make the new system meet the strict requirements of the six types of standards, it is indeed the most common and easiest solution to reduce the effect of crosstalk by increasing the spatial distance between lines. Using this method can reduce the difficulty of re-designing the connector, while the cable production process is also relatively simple. Therefore, the choice of most vendors is to use a cross isolation device in the traditional cable structure to achieve six types of Transmission Performance. This is the main impression of many users on the physical structure difference between Category 6 systems and traditional category 5/Category 5 systems. As a result, many people associate cross isolation with Category 6 systems.

However, in addition to using this cross isolation design method, is there any other design method to meet the transmission requirements proposed by the six types of international standards? The answer is yes.

The cat6 system is an end-to-end channel system. The link includes jumper, module, horizontal cable, and distribution frame. Improve the performance of the entire system, including cables and connectors. Therefore, if both the plug-in and Cable Design are improved, you can use a simpler physical structure to meet the requirements of the six types of systems. This is the emergence of the word isolation design.