1, white orange
2. Citrus
3. White and green
4. Blue
5. White and blue
6. Green (surname); green
7. White brown
8. brown
The other end is also the line sequence of 568B standard. In this case, if we connect the network cable with the crystal head, it will be used to connect hubs, routers and so on. But if you want to connect two computers with a network cable, you need a reverse line (cross line).
That is, one end adopts the above-mentioned 568B wiring standard.
On this basis, the other end switches the positions of line 1 3 and lines 2 and 6 among the eight lines, and the line order of network lines becomes
1, white and green
2. Green (surname); green
3. White and orange
4. Blue
5. White and blue
6.citrus
7. White brown
8. brown
This is the 568A standard of 100M network cable, which is what we usually call the anti-line or cross-line.
One end 568B and one end 568A are arranged and clamped to complete a network cable suitable for direct connection between two computers.
Summary:
[b]568A standard [/b]: white green, green, white orange, blue, white blue, orange, white brown, brown.
[b]568B standard [/b]: white orange, orange, white green, blue, white blue, green, white brown, brown.
The interconnection of two computers is a cross line: one end adopts 568A standard and the other end adopts 568B standard;
When making the crystal head, let the elastic piece of the crystal head face outwards, with the wire inlet facing downwards. From left to right, according to the wiring sequence above, completely insert the wire (subject to seeing the copper core of the twisted pair at the top of the crystal head), and then clamp it with a wire clamp, and you can do it!
Related introduction:
RJ-45 plug is a kind of plastic connector which can only be inserted in a fixed direction and automatically prevent it from falling off, commonly known as "crystal head". The technical term is RJ-45 connector (RJ-45 is a network interface specification, and RJ- 1 1 interface is the "telephone interface" that we usually use to connect telephone lines). It is called ""because of its glittering and translucent appearance. RJ-45 plugs must be installed at both ends of the double-sided adhesive tape before they can be plugged into the RJ-45 interface of a network card (NIC), hub or switch for network communication.
Local area network (LAN) is to connect computers or terminals with each other through the network, follow certain protocols, exchange information and realize resource sharing. Commonly used network cables are: twisted pair, coaxial cable and optical fiber. Twisted pair can be divided into shielded twisted pair (STP) and unshielded twisted pair (UTP) according to whether the metal mesh sheath shielding layer is added or not. From the point of view of cost performance and maintainability, most LANs use UTP unshielded twisted pair as the transmission medium of wiring.
UTP network cable is composed of twisted pair with a certain length and RJ45 crystal head.
Twisted pair is made up of eight wires of different colors twisted in four pairs. The function of twisted pair is to minimize the influence of electromagnetic radiation and external electromagnetic interference. In EIA/TIA-568 standard, twisted pair is divided into:
Class III, Class IV and Class V lines. Three types and five types of lines are most commonly used in the network, and there are more than six types at present.
To make a good network cable, connect RJ45 crystal head to RJ45 socket of network equipment such as network card or hub. Correspondingly, RJ45 plugs and sockets are also divided into three or five types of electrical characteristics. RJ45 crystal head is made of metal sheet and plastic. There are eight concave monks in the front end of RJ45 crystal connector needed to make network cable, which is referred to as "position" for short.
There are eight metal contacts in the groove, which is called "contact" for short, so there is another name for it in the industry. Special attention should be paid to the pin serial number of RJ45 crystal head. When the metal piece is facing us, the pin serial number is 1 ~ 8 from left to right. The serial number is very important for network connection, so you can't make a mistake.
The wiring standard of EIA/TIA stipulates the wiring sequence of two kinds of twisted pairs, 568a and 568b.
568a standard:
Green white-1, green -2, orange white -3, blue -4, blue white -5, orange 568b standard:
Orange white-1, orange white -2, green white -3, blue -4, blue white -5, green -6, brown white -7 and brown white -8.
("Orange white" refers to light orange, or cables with orange dots or stripes on the white line, which is also applicable to green white, brown white and blue white).
The order of twisted pair should correspond to the pin number of RJ45 connector.
In order to maintain the best compatibility, EIA/TIA 568b standard is widely used to make network cables. Note: Only one network cable standard can be used for the whole network wiring. If the standards are not uniform, it will be chaotic for several people to work together; What's more, once cable errors occur in the construction process, it is difficult to find and eliminate them in the bundled cables. I strongly recommend the uniform adoption of the 568b standard.
In fact, the network cable of 10 m Ethernet only uses the cores numbered 1, 2, 3 and 6 to transmit data, that is, 1 and 2 are used for sending, and 3 and 6 are used for receiving. In terms of color, orange, white and orange are used for sending; Green, white and green are used for receiving; 4, 5, 7 and 8 are bidirectional lines.
100 m and 1000 m network cards need four pairs of wires, that is, all eight cores are used to transmit data. Because 10m network card can use the network cable made in 100m mode; Moreover, twisted pair provides four pairs of wires, which are no longer distinguished in daily life. 10m network cards are generally used as network cables in 100m mode.
In addition, according to the different network devices connected at both ends of the network cable, the network cable can be divided into straight lines (parallel lines) and crossed lines. Straight lines (parallel lines) are network lines made according to 568a standard -6, brown-white -7, brown-white -8 or 568b standard. However, the line sequence of the crossing line is changed a little on the basis of the straight line: 1 and 3 are switched at one end of the cable, and 2 and 6 are switched. That is, one end of the intersection line remains unchanged (straight line sequence), and at the other end, 1 and 3 are inverted, and 2 and 6 are inverted.
The line sequence at both ends of the intersection line is as follows:
One end (unchanged) and the other end (switch two)
Orange white 1 3 green white
Orange 2 6 green
Green and white 3 1 orange and white
Blue 4 4 blue
Blue and white 5 5 blue and white
Green 6 2 orange
Brown and white 7 7 Brown and white
Brown 8 8 brown
Straight-through lines are used to connect:
1. Host and switch/hub;
2. Routers and switches/hubs
Crosshairs are used to connect:
1. switch and switch;
2. Moderator and moderator;
3. Hubs and hubs;
4. Hubs and switches;
5. The host and router are directly connected.
In practice, it can be generally understood as follows:
1. Devices of the same type are connected by cross lines, and devices of different types are connected by straight lines;
2. Routers and PCs belong to DTE equipment, and switches and hubs belong to DCE equipment;
3. There are usually two standard methods for 3.RJ45 network connectors: 568A and 568B. According to the same standard, it is a straight line, and different standards are intersecting lines.
In any case, when testing with RJ-45 line tester after the final completion, all eight indicators should flash in turn.