Ethereum cable

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3. Detailed explanation of the connection of the crystal head of the network cable
detailed explanation of the connection of the crystal head of the network cable LAN is to connect indivial computers or terminals with each other through the network, follow certain protocols, exchange information and realize resource sharing. Network cable commonly used are: twisted pair, coaxial cable, optical fiber, etc. Twisted pair can be divided into shielded twisted pair (STP) and unshielded twisted pair (UTP) according to whether the shielding layer of metal mesh is added. From the perspective of cost performance and maintainability, most LANs use unshielded twisted pair (UTP) as the transmission medium for routing. UTP network cable is composed of a certain length of twisted pair and RJ45 crystal head. The twisted pair consists of 8 wires of different colors, which are divided into 4 pairs and twisted together. The function of twisted pair is to rece the influence of electromagnetic radiation and external electromagnetic interference as much as possible. In EIA / tia-568 standard, twisted pair is divided into three kinds of wires, four kinds of wires and five kinds of wires according to their electrical characteristics. In the network, the most commonly used are three kinds of lines and five kinds of lines. At present, there are more than six kinds of lines. The RJ45 crystal head should be connected to the RJ45 socket of network card or hub. Accordingly, RJ45 plug socket is also divided into three or five types of electrical characteristics. RJ45 crystal head is made of metal sheet and plastic. There are eight concave holes in the front end of RJ-45 crystal joint, which is called "position" for short. There are a total of 8 metal contacts in the groove, referred to as "8C" (contact), so the instry has the nickname "8p8c". What needs special attention is the pin number of RJ45 crystal head. When the metal piece faces us, the pin number from left to right is 1-8, which is very important for network connection. The maximum transmission distance of twisted pair is 100m. If you want to increase the transmission distance, you can install repeaters between two twisted pairs, up to four repeaters. If four repeaters are installed to connect five network segments, the maximum transmission distance can reach 500m. The wiring standard of EIA / TIA specifies the wire sequence 568a and 568B of two kinds of twisted pair. Standard 568a: green white-1, Green-2, orange white-3, blue-4, blue white-5, orange-6, brown white-7, brown-8 standard 568B: orange white-1, orange-2, green white-3, blue-4, blue white-5, green-6, brown white-7, brown-8 to maintain the best compatibility, EIA / tia568b standard is widely used to make network cable. In the whole network wiring, a kind of wiring mode is applied, but the network wiring with RJ-45 socket at both ends is feasible in the network, whether adopting 568a standard or 568B standard. The order of twisted pair is corresponding to the pin serial number of RJ45. The network cable of 10M Ethernet uses 1, 2, 3 and 6 core wires to transfer data, while the network card of 100m needs four pairs of wires. Because the 10m network card can use the network cable made in 100m mode; The twisted pair also provides four pairs of wires, so even if 10m network card is used, the network cable is usually made in 100m mode. The standard requires that 1, 2, 3, 6, 4, 5, 7 and 8 wires must be twisted in pairs. This is because, in the data transmission, in order to rece and suppress the external interference, the transmitted and received data are transmitted in differential mode, that is, each pair of wires twisted together to transmit a differential signal (this is also the origin of the name of twisted pair). The so-called differential signal means that one wire transmits the signal in a positive level mode and the other wire transmits the same signal in a negative level mode. When there is an interference signal in the line, its influence on the two wires is the same. Therefore, when the differential signal is restored at the receiving end, the interference signal can be shielded (it can be understood as the subtraction operation of two differential signals). From the principle of interference suppression of twisted pair, we can see that the purpose of twisted pair is to suppress interference signal and improve transmission quality; Therefore, when we make the joint of twisted pair, we must not separate a pair of wires that transmit differential signal, otherwise it will greatly affect the transmission quality of the network. The following describes several application environment twisted pair proction methods. MDI indicates that this port is a cascade port, while mdi-x indicates that this port is a normal port. 1. Connection between Ethernet network card and hub: when PC and other network devices are connected to hub, the network cable used is straight through line, and the two ends of twisted pair cable should be connected one by one. At this time, hub is mdix port and PC is MDI port. The 10Mbps network cable only needs one correspondence at both ends of the twisted pair. It is not necessary to consider the order of different color lines. If the 100m speed is used for connection, it must be made in strict accordance with the EIA / tia568a or 568B wiring standard. The wiring reference is as follows.

4. Brief introction to the proction and connection of network cable
LAN is to connect indivial computers or terminals with each other by means of communication lines, follow certain protocols, exchange information and realize resource sharing. Among them, communication lines, that is, transmission media commonly used are: twisted pair, coaxial cable, optical fiber, etc. From the perspective of cost performance and maintainability, most LANs use unshielded twisted pair (UTP) as the transmission medium for wiring
LAN is to connect indivial computers or terminals with each other by means of communication lines, to exchange information and to share resources according to certain coordination. Among them, communication lines, that is, transmission media commonly used are: twisted pair, coaxial cable, optical fiber, etc. From the perspective of cost performance and maintainability, most LANs use unshielded twisted pair (UTP) as the transmission medium for wiring

the network cable is composed of twisted pair and RJ45 head with a certain distance. Twisted pair consists of 8 wires of different colors, which are divided into 4 pairs and twisted together. The function of group twisting is to rece the influence of electromagnetic radiation and external electromagnetic interference as much as possible. Twisted pair can be divided into shielded twisted pair (STP) and unshielded twisted pair (UTP) according to whether or not the shielding layer of metal mesh sleeve is added. In EIA / tia-568a standard, twisted pair is divided into three types according to electrical characteristics: three types, four types and five types. In the network, the most commonly used lines are three kinds of lines and five kinds of lines. At present, there are more than six kinds of lines. The third kind of twisted pair is commonly used as the data and voice transmission of 10Mbps Ethernet in LAN, which conforms to the standard of IEEE802.3 10base-t. The fifth type of twisted pair currently occupies the largest LAN market, with the highest speed up to 100Mbps, meeting the IEEE802.3 100Base-T standard. The RJ45 crystal head should be connected to the RJ45 socket of network card or hub. Accordingly, RJ45 plug socket is also divided into three or five types of electrical characteristics. RJ45 crystal head is made of metal sheet and plastic, especially the pin serial number. When the metal sheet faces us, the pin serial number is 1-8 from left to right, which is very important for network connection. The maximum transmission distance of twisted pair is 100 meters

the wiring standard of EIA / TIA specifies the wire sequence 568a and 568B of two kinds of twisted pair

standard 568a: orange white-1, orange-2, green white-3, blue-4, blue white-5, green-6, brown white-7, brown-8

standard 568B: green white-1, Green-2, orange white-3, blue-4, blue white-5, orange-6, brown white-7, brown-8

a kind of routing method is applied in the whole network wiring, but the network connection with RJ-45 plug at both ends is common in the network, whether it is using the termination method a or the termination method B. The sequence of twisted pair corresponds to the pin number of RJ45 head. The network cable of 10M Ethernet uses 1, 2, 3 and 6 cores to transfer data, while the network cable of 100M Ethernet uses 4, 5, 7 and 8 cores to transfer data. Why are 4 pairs (8-core) twisted pair used now? This is mainly to meet the wiring requirements of various user equipment without changing the infrastructure. For example, we can use one pair of twisted wires to realize voice communication at the same time< The stipulations of 100base-t4 RJ-45 twisted pair are as follows:

1 and 2 are used for transmitting, 3 and 6 for receiving, and 4, 5, 7 and 8 are bidirectional lines

1 and 2 wires must be twisted in pairs, 3 and 6 twisted in pairs, 4 and 5 twisted in pairs, 7 and 8 twisted in pairs.

5. The color of one port is different from others. That one is connected to the external network cable. The other ports are the same

6. The function of cable arrangement:
1. Cable arrangement is used for data transmission of moving parts and active areas, such as the data cable connecting the internal computer motherboard to the hard disk and optical drive, and the mobile phone motherboard to the display screen
2. The power supply for the system mole is arranged to ensure the normal operation of the mole<
extension of knowledge points:
flat wires have excellent electrical properties, dielectric properties and heat resistance. The wires can be moved, bent and twisted without damaging the wires, and can conform to different shapes and special package sizes.

7. Example of remote programming and debugging of rectangular N80 series PLC via Ethernet< The connection between PLC and slave station equipment adopts standard RJ45 interface:
the connector of crystal head, and the connection mode is as follows:
1. The line arrangement order: take the line with left hand, the line head is outward, and the order is from left to right. Hold the plug in the right hand and insert the metal spring upward into the core
2. The order of arrangement is: orange white, orange, green white, blue, blue white, green, brown white and brown.

8. In the future, this kind of silly B problem can be directly searched on Google or Internet. Don't waste network resources here<

there are many kinds of friendly network cable methods. I can give you a very detailed document. If you look at it for yourself, it will help a little.
LAN is to connect indivial computers or terminals with each other through the network, follow certain protocols, exchange information, and share resources. Network cable commonly used are: twisted pair, coaxial cable, optical fiber, etc. Twisted pair can be divided into shielded twisted pair (STP) and unshielded twisted pair (UTP) according to whether the shielding layer of metal mesh is added. From the perspective of cost performance and maintainability, most LANs use unshielded twisted pair (UTP) as the transmission medium for routing
UTP network cable is composed of twisted pair and RJ45 crystal head
twisted pair consists of 8 wires of different colors, which are divided into 4 pairs and twisted together. The function of twisted pair is to rece the influence of electromagnetic radiation and external electromagnetic interference as much as possible. In EIA / tia-568 standard, twisted pair is divided into three types according to electrical characteristics:
three types, four types and five types. In the network, the most commonly used are three kinds of lines and five kinds of lines. At present, there are more than six kinds of lines
the RJ45 crystal head should be connected to the RJ45 socket of network card or hub. Accordingly, RJ45 plug socket is also divided into three or five types of electrical characteristics. RJ45 crystal head is made of metal sheet and plastic. There are eight concave holes in the front end of RJ-45 crystal joint, which is called "position" for short
there are eight metal contacts in the groove, referred to as "8C" (contact), so the instry has the nickname "8p8c". What needs special attention is the pin number of RJ45 crystal head. When the metal piece faces us, the pin number from left to right is 1-8, which is very important for network connection
the maximum transmission distance of twisted pair is 100m. If you want to increase the transmission distance, you can install repeaters between two twisted pairs, up to four repeaters. If four repeaters are installed to connect five network segments, the maximum transmission distance can reach 500m
the wiring standard of EIA / TIA specifies the wire sequence 568a
and 568B of two kinds of twisted pair
standard 568a:
green white-1, Green-2, orange white-3, blue-4, blue white-5,
orange-6, brown white-7, brown-8
standard 568B:
Orange white-1, orange-2, green white-3, blue-4, blue white-5,
green-6, brown white-7, brown-8
in order to maintain the best compatibility, EIA / TIA 568B standard is widely used to make network cable. In the whole network wiring, a kind of wiring mode is applied, but the network wiring with RJ-45 socket at both ends is feasible in the network, whether adopting 568a standard or 568B standard. The order of twisted pair is corresponding to the pin serial number of RJ45. The network cable of 10M Ethernet uses 1, 2, 3 and 6 core wires to transfer data, while the network card of 100m needs four pairs of wires. Because the 10m network card can use the network cable made in 100m mode; The twisted pair also provides four pairs of wires, so even if 10m network card is used, the network cable is usually made in 100m mode
the standard requires that 1, 2, 3, 6, 4, 5, 7 and 8 wires must be twisted in pairs. This is because, in data transmission, in order to rece and suppress external interference, the transmitted and received data are transmitted in differential mode, that is, each pair of wires twisted together to transmit a differential signal
number (this is also the origin of the name of twisted pair)
the so-called differential signal means that one line transmits the signal in a positive level mode and the other line transmits the same signal in a negative level mode. When interference signal appears in the line, its influence on the two lines is the same. Therefore, when the differential signal is restored at the receiving end, the interference signal can be shielded (it can be understood as subtraction operation of two differential signals). From the principle of interference suppression of twisted pair, we can see that the purpose of twisted pair is to suppress interference signal and improve transmission quality; Therefore, when we make the joint of twisted pair, we must not separate a pair of wires that transmit differential signal, otherwise it will greatly affect the transmission quality of the network
the following describes the proction methods of twisted pair in several application environments
MDI indicates that this port is a cascade port, while mdi-x indicates that this port is a normal port
1. Connection between Ethernet network card and hub:
when network devices such as PC are connected to hub, the network cable used is straight through line, and the two ends of twisted pair should be connected one by one. At this time, hub is mdix port and PC is MDI port. The 10Mbps network cable only needs one correspondence at both ends of the twisted pair. It is not necessary to consider the order of different color lines. If the 100m speed is used for connection, it must be made in strict accordance with the EIA / tia568a or 568B wiring standard. The wiring reference is as follows

name pin cablecolor pin name
TX + 1 White Orange 1 TX +
TX - 2 Orange 2 TX -
RX + 3 white green 3 RX +
4 LAN 4
5 Prynne 5
RX - 6 Green 6 RX -
7 White Brown 7
8 Brown 8


2, At the same time, it is connected with a straight line. If the hub has no dedicated level connection or cannot use the level connection, it must use mdi-x port level connection. In this case, we can use the cross line to achieve the purpose. The connection reference is as follows

name nic1 nic2 name
TX + 13 RX +
TX - 26 RX -
RX + 31 TX +
RX - 62 TX -


direct connection between 3.100m hub or two computers:
we should also know that the length of network cable between cascade hubs should not exceed 100m, and the cascade connection of hub should not exceed 4 levels. As the cross line is rarely used, special marks should be made to avoid the line failure caused by the misuse of straight line in the future. In addition, the cross network cable can also be used for direct connection of two microcomputers. Please refer to the following table for connection< br />
name pin pin name
TX_ D1+ 1 3 RX_ D2+
TX_ D1- 2 6 RX_ D2-
RX_ D2+ 3 1 TX_ D1+
RX_ D2- 4 2 TX_ D1-
BI_ D3+ 5 7 BI_ D4+
BI_ D3- 6 8 BI_ D4-
BI_ D4+ 7 4 BI_ D3+
BI_ D4- 8 5 BI_ D3 -

finally, it is necessary to conct on-off test on the line. When testing with the cable tester, all green lights should flash in turn. The most common method of software debugging is to use the ping command of Windows 95 and windows 98. If the workstation receives the response from the server, it indicates that the line is normal and the network protocol is installed normally, which is the basis for the normal work of the network application software.

9. Network cable has optical fiber, other inside should have copper handle!

10.

Both gigabit network and 100m network transmit CLK clock signal and data signal, and the network cable needs two-way transmission, so it needs to transmit TX_ CLK、TX_ DATA、RX_ CLK、RX_ There are four kinds of data signals, so four wires are needed

according to the technology and needs at that time, four wires were used in the 100 MB network and four wires were reserved for standby, while the transmission speed of the Gigabit network was faster, the distance was longer and the requirements were higher. In order to achieve this purpose and rece interference, differential transmission was selected (we can see that the wires inside were twisted together), so eight wires were needed

There are two kinds of common RJ45 interfaces: DTE (data terminal equipment) used for Ethernet card, router Ethernet interface and DCE (digital communication equipment) used for switch. When two devices of the same type use RJ45 interface to connect and communicate, cross line connection must be used

if the DTE type interface and the DTE type interface are connected without cross connection of pins, the pins to be touched are all data receiving (transmitting) pins, so they cannot communicate. In addition: some DCE type equipment will automatically negotiate with the other party. In this case, the connection can be through line or parallel line< br />