568 a standard

Pin order media are directly connected to the signal color

1 TX+(transport) white and green

2 TX-(transport) green

3 RX plus white orange

No blue

Don't use white or blue

6 RX minus (receiving) oranges

Do not use white or brown

Do not use brown

568 b standard

Pin order media are directly connected to the signal color

1 TX+(transfer white orange

2 TX-(transport) oranges

3 RX plus white and green

No blue

Don't use white or blue

6 RX minus (receiving) green

Do not use white or brown

Do not use brown

5 kinds of colors. Twine can play the role of anti-interference!!!!!8 lines line 1236 of them were transmission of digital signal that is used in our network data transmission is the analog signal is 45 telephone pulse signal transmission of 78 is for IP phone POE is required for power supply, of course, in fact in the 100 m under the network running, usually eight core will all use, higher requirements for 100 m network transmission lines, not only should use 1 2 3 6, or network operation will be unstable.

Understand the principle and practice of super five twisted pair wires

First of all, let's have a specific understanding of what twisted pair is

1, twisted pair: as a transmission medium, it is made up of two thin copper wires coated with insulating materials wound together at a certain ratio.

Related pictures of this topic are as follows:

The picture shows the superfive twisted pairs of wires, consisting of four pairs of twined wires, with a total of eight lines.

2. Why do you twine two wires?

Because this interwinding changes the electrical properties of the cable.This not only reduces the crosstalk itself, but also minimizes the interference of signals from other cables on this pair of cables.

3. Twisted-pair cable classification:

1) twisted pair can be divided into 2 pairs, 4 pairs and 25 pairs according to the logarithm of twisted pair.(e.g. 2 pairs for telephone, 4 pairs for network transmission, and 25 pairs for telecommunication large logarithmic cable)

2) according to whether there is shielding layer, it can be divided into two categories: shielded twisted pair (STP) and unshielded twisted pair (UTP).

3) according to frequency and SNR, it can be divided into 3 categories, 4 categories, 5 categories and 5 categories.Now there are six or even seven lines in many places.At least three categories are used in computer network communications.The following are the descriptions of various lines:

Class 1: mainly used for voice transmission (class 1 standard is mainly used for telephone cables before the early 1980s), not for data transmission.

Class 2:1MHz transmission frequency, used for voice transmission and data transmission with a maximum transmission rate of 4Mbps, commonly seen in the old token network using the 4Mbps standard token transfer protocol.I"

Class iii: cables currently specified in the ANSI and EIA/TIA568 standards.The transmission frequency of the cable is 16MHz, which is used for voice transmission and data transmission with the maximum transmission rate of 10Mbps, mainly for 10base-t

Four types: the transmission frequency of this cable is 20MHz, which is used for voice transmission and data transmission with the highest transmission rate of 16Mbps. It is mainly used for token based LAN and 10base-t / 100base-t.

Class 5: this kind of cable increases the winding density, coat a kind of high quality insulation material, transmission frequency of 100MHz, used for voice transmission and data transmission with the highest transmission rate of 100Mbps, mainly used for 100base-t and 10base-t networks, which is the most commonly used Ethernet cable.

4, twisted pair performance indicators for twisted pair, the user is most concerned about the performance of the performance of several indicators.These include attenuation, near-end crosstalk, impedance characteristics, distributed capacitance, dc resistance, and so on.

(1) decay.60

Attenuation is the signal loss measurement along the link.Attenuation is related to the length of the cable. As the length increases, the signal attenuation also increases.Attenuation is expressed in "db" as the ratio of signal strength from the source transmitter to the receiver.Since attenuation varies with frequency, attenuation at all frequencies in the range of application should be measured.

(2) near-end crosstalk + :

Crosstalk is divided into near crosstalk and far crosstalk (FEXT). The tester mainly measures NEXT. Due to the circuit loss, the value of FEXT has little influence.Near-end crosstalk (NEXT) loss is the measurement of signal coupling from one pair of lines to another in a UTP link.For UTP links, NEXT is a key performance metric and one of the most difficult to measure accurately.With the increase of signal frequency, the measurement difficulty will increase.

Two, super five types of non - shielded twisted pair

What we use in computer communication networks today is basically "superfive unshielded twisted-pair cables."The two ends of the cable are pressed into the RJ45 crystal head in a certain sequence of lines, which is commonly referred to as "network cable".

Picture is RJ45 crystal head!

1. What are the T568A and T568B standards?

These are two kinds of international standard wire sequences for the purpose of achieving the performance index and unified wiring specification of super five twisted pair wires.

(think about this: if there is no standard for making RJ45 crystal head, then when one end of a thread made by someone else has a problem with the crystal head, you have to look at the thread sequence on the other end and come back to make the RJ45 crystal head on this end.It is also possible that crosstalk is caused by not using the correct winding pair.

123, 45678,

The line order of T568A is: white green, green, white orange, blue, white blue, orange, white brown, brown

The line order of T568B is: white orange, orange, white green, blue, white blue, green, white brown, brown

2. Parallel and cross lines (reverse wiring)

1) first, let's see how these two kinds of lines are made:

Parallel lines use the same wiring standard at both ends.In general, the industry USES the T568B standard!Remember!!!Cross lines use T568A at one end and T568B at the other end.