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2016年9月27日星期二

Cat 5e or Cat 6 - Which Do You Choose?

As one type of copper cabling, twisted pair wiring is widely adopted for Ethernet networks which wraps the two conductors of a single circuit together. Nowadays, many kinds of twisted pair cables are available in the market. To specify the cable wiring standards, the Electronic Industries Alliance (EIA) and Telecommunications Industry Association (TIA) have defined twisted pair cables into a series of categories, such as Cat 5, Cat 5e, Cat 6, Cat 6a, Cat 7, etc. This article will put emphasis on the two common categories of Cat 5e and Cat 6 to see their differences and which one to choose for your application.
cat5e-cat6

Wiring Standards of Cat 5e & Cat 6
Two standards of T568A and T568B can be used to wire Cat 5e and Cat 6 Ethernet cables. The only difference between T568A and T568B is that the green/green strip and orange/orange strip wire positions are swapped. In general, T568B is more popular for office and commercial networks. But no matter which wiring standard you choose, the most important thing is to continue with the selected standard for consistency. The following picture shows the concrete structure of T568A and T568B wiring.
t568a-t568b

Differences Between Cat 5e & Cat 6
Speed
Data speed is important for cable selections. You have to choose the cable that is equivalent to what is running on it. As for Cat 5e cable, it can support 1 Gigabit Ethernet. While Cat 6 can support higher data rate of 10 Gigabit Ethernet. This is because Cat 6 cable performs up to 250 MHz, which is more than twice that of Cat 5e cable with 100 MHz.

Maximum Length
The common ground for Cat 5e and Cat 6 cables is that they are all designed for short distance data transmission because they are made of copper wires. If the cable is used for lower data rate transfer, both Cat 5e and Cat 6 are able to reach the maximum length of 100 meters. However, when the data rate achieves the maximum speed, Cat 5e cable can only reach 50 meters and Cat 6 with 37 meters.

Cost
Compared with Cat 5e cables, the cost of Cat 6 cables is typically 10 to 20% more expensive because of higher transmission speed. But the price of these cables are comparatively cheap, which only takes up a small portion of the total budget. For the consideration of your application, Cat 6 might be a better choice if higher data rate is required. The additional cost can save you more money in the long run.

Application
Traditionally, Cat 5e cable is run for the business telephones. But using Cat 6 cable with a phone might be a waste. Cat 6 is suited for broadband video and digital video applications because of the lower signal losses and better transmission performance at higher frequencies compared with Cat 5e.

Can We Use Cat 5e With Cat 6?
The answer is yes. Regardless of a possibly different coating on the pins, Cat 5e and Cat 6 are both employing the RJ45 plug standard which makes them compatible to each other. But you can only receive a limited speed of the lowest link in the chain. Therefore, if you want to receive the best performance of cables, you should better use the matching components for your application.

Conclusion
Cat 5e and Cat 6 are two different categories of twisted pair cabling. The major difference between them is the data speed. Cat 6 has a higher speed than Cat 5e which accordingly varies their maximum length, cost and application. All these factors are important for you to make a choice between Cat 5e and Cat 6. Moreover, if higher speed over long distance is demanded, fiber optic cables might be a better solution.

2016年6月15日星期三

Introduction to Categories of Twisted Pair

As one of the oldest types of cable ever invented, twisted pair cabling was first developed by Alexander Graham Bell in 1881. Since then, it has been widely deployed for telephone line network in America. Nowadays, the application of twisted pair has been extended worldwide mainly for outdoor land lines offering telephone voice service.

Generally speaking, twisted pair cabling is a kind of copper wiring that two conductors of a single circuit are twisted together. The purpose of using twisted pair is to offset electromagnetic interference (EMI) from external sources to stop degrading the performance of circuit. Also, different standards of twisted pair are specified into various categories as cat 1, cat 2, cat 3, cat 4, cat 5/5e, cat 6/6a, cat 7/7a, cat 8/8.1/8.2. And this article will give a brief introduction to some of the above categories.

twisted pair


Different Categories of Twisted Pair

1) Cat 5/5e
Cat 5 twisted pair cable is often used for structured cabling of computer networks. It is available to 10/100 Mbps speeds at up to 100 MHz bandwidth. However, it is now considered to be obsolete and replaced by cat 5e (enhanced). Cat 5e is one the most commonly used twisted pair cables at present. The biggest distinction between cat 5 and cat 5e is that cat 5e has a lower cross talk and its transmitting speed can reach up to 1000 Mbps.

2) Cat 6/6a
As a substitute of cat 5/5e, cat 6 twisted pair is applied to Gigabit Ethernet and other network physical layers. It supports up to 10 Gbps speed at 250 MHz. When used for 10GBASE-T applications, cat 6 has a reduced maximum length from 37 to 55 meters. But cat 6a (augmented) has been evolved to perform at up to 500 MHz, thus the maximum cable distance is longer than cat 6 of up to 100 meters.

3) Cat 7/7a
Cat 7 is the standard for twisted pair cabling used for 1000BASE-T and 10GBASE-T networks. It provides performance of up to 600 MHz with a maximum length of 100 meters. As for the cat 7a (augmented) cable, it has a higher frequency of 1000 MHz. Results show that it may be possible to support 40 GbE or even 100 GbE at a very short length.

4) Cat 8/8.1/8.2
Cat 8 is the USA standard specified by ANSI/TIA while cat 8.1 and cat 8.2 are specified by ISO/IEC for global application. All these three kinds of cat 8 twisted pairs are used for 25GBASE-T and 40GBSE-T at the maximum frequency of up to 2 GHz. Except cat 8 adopts cat 8 links, cat 8.1 uses class I links and cat 8.2 uses class II links. The key difference between class I and class II is that class II allows three different styles of connectors to be not compatible with one another, or with the RJ45 connector.

Conclusion
Twisted pair cables have been classified into different grades called categories. These standards especially formulate the data capacity of the cable. Higher categories are more expensive than lower ones, but most of cost is actually spent on labor force for installing the cables. And twisted pair cables under cat 5 are not recommended now. Higher categories are the future trends for network cabling.