Shulou(Shulou.com)06/01 Report--

The common twisted pair wires are Category 3, Category 5 and Super Category 5, Category 6, and the latest Category 7. The former line diameter is thin and the latter line diameter is thick, the model is as follows:

The first type of cable is mainly used for voice transmission (a kind of standard is mainly used for telephone cables before the early 1980s), which is different from data transmission.

Category II line: the transmission frequency is 1MHZ, which is used for voice transmission and data transmission of the highest transmission rate 4Mbps. It is common in old token networks that use the 4MBPS specification token passing protocol.

Category 3 cable: the cable specified in the ANSI and EIA/TIA568 standards, the transmission frequency of this cable is 16MHz, used for voice transmission and data transmission with a maximum transmission rate of 10Mbps is mainly used for 10BASE--T.

Category four cables: the transmission frequency of this kind of cable is 20MHz, and the data transmission for voice transmission and maximum transmission rate 16Mbps is mainly used for token-based LAN and 10BASE-T/100BASE-T. 5)

Category 5 cable: this kind of cable increases the winding density and covers a high-quality insulating material with a transmission rate of 100MHz. It is used for voice transmission and data transmission with the highest transmission rate of 100Mbps, mainly for 100BASE-T and 10BASE-T networks. This is the most commonly used Ethernet cable.

Super Category 5 lines: Super Category 5 has low attenuation, low crosstalk, higher ratio of attenuation to crosstalk (ACR) and signal-to-noise ratio (StructuralReturn Loss), and smaller delay error, so the performance is greatly improved. Super Category 5 lines are mainly used for Gigabit Ethernet (1000Mbps).

Category 6 cable: the transmission frequency of this kind of cable is 1MHz~250MHz, and the comprehensive attenuation crosstalk ratio (PS-ACR) of type 6 cabling system in 200MHz should have a large margin, which provides 2 times more bandwidth than category 5. The transmission performance of six types of cabling is much higher than that of more than five standards, and it is most suitable for applications where the transmission rate is higher than 1Gbps. An important difference between category 6 and category 5 is that it improves the performance of crosstalk and echo loss. for the new generation of full-duplex high-speed network applications, excellent echo loss performance is very important. The basic link model is cancelled in the six types of standards, and the cabling standard adopts a star topology, and the required wiring distance is that the length of the permanent link can not exceed 90m and the channel length can not exceed 100m.

Super Category 6 cable: Super Category 6 cable is an improved version of Category 6 cable. It is also an unshielded twisted pair cable specified in ANSI/EIA/TIA-568B.2 and ISO Category 6 / E standards. It is mainly used in gigabit networks. Like Category 6 lines, the transmission frequency is 20000250 MHz, and the maximum transmission speed can reach 1000 Mbps, but there is a great improvement in crosstalk, attenuation and signal-to-noise ratio.

Category 7 cable: this line is the latest twisted pair in the ISO Class 7 / F standard, which is mainly designed to adapt to the application and development of 10 Gigabit Ethernet technology. However, it is no longer an unshielded twisted pair, but a shielded twisted pair, so its transmission frequency can reach at least 500MHz, which is more than twice that of Category 6 and super Category 6 lines, and the transmission rate can reach 10 Gbps. Twisted pair can be divided into unshielded twisted pair (UTP=UNSHIELDED TWISTEDPAIR) and shielded twisted pair (STP=SHIELDED TWISTEDPAIR). The outer layer of shielded twisted pair cable is coated with aluminum and platinum to reduce radiation, but it can not completely eliminate radiation. The price of shielded twisted pair cable is relatively high, and it is more difficult to install than unshielded twisted pair cable. Unshielded twisted pair cable has the following advantages: unshielded jacket, small diameter, saving space; light weight, easy to bend, easy to install; minimize or eliminate near-end crosstalk; flame retardancy; independence and flexibility, suitable for structured integrated cabling.

The difference between super category 5 and type 6 network cables

There are three kinds of common network cables in LAN: twisted pair, coaxial cable and optical cable. Twisted pair is a data transmission line composed of many pairs of wires. Its characteristic is that it is cheap, so it is widely used, such as our common telephone lines. It is used to connect to the RJ45 crystal head. There are two kinds of STP and UTP, and we often use UTP.

Which kind of good method to choose and purchase network cable

1. Distinguish from the network cable logo

The logo of Category 3 lines is "CAT3", with a bandwidth of 10m, which is basically eliminated for 10 megabit networks; the logo of Category 5 lines is "CAT5" with a bandwidth of 100m, which is suitable for networks below 100m; the logo of Category 5 lines is "CAT5E" with a bandwidth of 155m, which is the mainstream product; the logo of Category 6 lines is "CAT6" with a bandwidth of 250m, which is used for erecting gigabit networks, which is the trend of future development. Secondly, by looking at this way, we can distinguish most false Category 5 / Super Category 5 lines. The characters printed on the real Category 5 online plastic foreskin are very clear, smooth and basically non-jagged. The printing quality of the handwriting of fake goods is poor, some of the fonts are not clear, and some are seriously jagged. Authentic category 5 lines are marked with the word "cat5", while over category 5 lines are marked with the word "5e", while fake goods are usually marked with capital letters such as "such as CAT5" and "5e".

2. Feel with your hands

If the "look" method is still unable to distinguish, we can further through the "touch" method to feel the difference between true and false Category 5 / Super Category 5 lines in the material. True Category 5 / Super Category 5 wires are relatively soft, mainly in order to meet the needs of different network environments. Copper wire is generally used as wire core in twisted pair cables, which is relatively soft (because some network environments may require network wires to bend at a small angle. If the wire is hard, it is easy to break the circuit. In order to reduce the cost, some unscrupulous manufacturers add other metal elements to the copper, so the wire is hard and not easy to bend, and it is easy to break the wire in use.

3. Cut with a knife

In this step, you only need to remove the plastic foreskin from the outside of a small cut with scissors to expose 4 pairs of core wires. Here we still through the "look" method to further distinguish, true Category 5 / Super Category 5 wire 4 pairs of core wire in the white one should not be pure white, but with the paired color of the core line whitening, this is mainly to facilitate users in the production of crystal head to distinguish the line pair. The fakes are usually pure white or the design is not obvious. Another point is the winding density of 4 pairs of core wires, the true Category 5 / Super Category 5 winding density is moderate and the direction is counterclockwise. The false thread is usually very dense and the direction may be clockwise (less), mainly because it is easier to make, so the production cost is lower.

4. Burn with fire

You can test the twisted pair in a high temperature environment to see if the rubber outside the network cable will become soft at 35 ℃ to 40 ℃, and the authentic network cable will not become soft, so the fake one may not be true; and the glue outside the real network cable is flame retardant, while some fake ones do not have flame retardancy and do not meet safety standards, so you might as well try when buying.

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