Twisted Pair wires have two Connection Methods: EIA/TIA 568b standard and EIA/TIA 568a standard. The specific method is as follows:

The cabling method and strategy of twisted pair wires in the network during network construction, the quality of the twisted pair wires may affect the overall performance of the network. The connection of twisted pair wires between various devices is also very exquisite and should be connected according to specifications. This article mainly introduces the standard connection method of twisted pair wires and their connection methods with various devices. The purpose is to keep everyone familiar with the rules, improve work efficiency, and ensure the normal operation of the network.
The standard connection method of twisted pair wires is generally used for star network cabling, each twisted pair wires are connected to various network devices through the RJ-45 connectors installed at both ends (commonly known as the crystal head. The standard connection method of twisted pair wires is not specified at will. The purpose is to ensure the symmetry of the cable connector layout, so that interference between cables in the connector can be offset. Cat5e cables are the most commonly used network cables for network cabling. They are divided into two types: shielded and unshielded. If it is used outdoors, The Screen Shield is better. Generally, it is enough to use non-shielded five-category cables in the room. Because no Screen Shield is provided, the cables are relatively soft, but their connection methods are the same. In general, there are four pairs of lines twisted together in the cat5e category and marked with different colors.

Twisted Pair wires have two Connection Methods: EIA/TIA 568b standard and EIA/TIA 568a standard. The specific method is as follows: t568a line sequence 1 2 3 4 5 6 7 8 green white green orange white blue white orange brown white brown t568b line sequence 1 2 3 4 5 6 7 8 orange white orange green white blue white green brown white brown straight line: both ends are connected in the t568b line sequence. Crossover line: one end is connected in t568a line Order and the other end is connected in t568b line order.

When we create a network cable at ordinary times, if we do not follow the standard connection, although sometimes the line can be connected, but the interference between various lines within the line cannot be effectively eliminated, resulting in an increase in the error rate of signal transmission, this affects the overall network performance. Only by building standards can we ensure the normal operation of the network and facilitate the maintenance work in the future. Connection method between devices 1. When the network card is directly connected to the 10 m or M network card of the network card, the hub is not needed. Cross-line connection method should be used. 2. the NIC and optical transceiver module install the NIC on the computer and set it up. Connect the transceiver to the power supply and operate it in strict accordance with the Instructions. Connect the computer and the transceiver with twisted pair wires. The twisted pair wires should be connected to the crossover cable; use optical jumpers to connect two receivers. For example, if the transceiver is single-mode, the jumper is also single-mode. When the optical jumper is connected, one end is connected to RX, and the other end is connected to TX. However, many optical modules now have control functions, and can be used for cross and direct connections. Figure 2 shows the basic network connection of the optical transceiver.
[Img] A twisted pair is used to connect a computer to a transceiver. The twisted pair is a direct connection. 4. The NIC and switch twisted pair wires are connected through a direct connection. 5. the two hubs (or switches) of a hub and a hub (vswitch and vswitch) are connected through a twisted pair cascade. The distribution of the midline pairs of the twisted pair is different from that of the nic and hub. A crossover line is required. This situation applies to connections between hubs that do not indicate dedicated cascade ports. For convenience, many hubs provide a port dedicated to connecting to another hub, when cascade these hubs, the twisted pair wires should be connected through a direct connection. How do users determine whether their hubs (or switches) need cross-line connections? The main methods are as follows:★View the manual. If the hub requires a cross-line connection during cascade, it is generally described in the device manual.★View the connection port. If the Hub does not need to cross lines during cascade, one or two dedicated interconnection ports are provided in most cases, and corresponding labels are provided, for example, "Uplink", "MDI", and "out to hub" indicate that a direct connection is used.★This is the most useful method for actual measurement. You can first create two twisted pair wires for testing, one of which is a straight line and the other is a cross line. Then, use one of the two hubs to connect to the two hubs. Observe the indicator lights corresponding to the connection port. If the indicator light is on, the connection is normal. Otherwise, use another twisted pair cable for testing. 6. The vswitches and hubs can also be connected in cascade mode. Level-1 connectivity is often an effective solution for connecting vswitches of different brands and between vswitches and hubs. Another way to expand the number of ports is stack. Stacking is the quickest and most convenient way to expand ports, but not all switches support stacking. Stack usually requires a dedicated stack cable and a dedicated stack module. In addition, the same group of stack switches must be of the same brand and must be set after the physical connection is completed to run properly. For the stacking method, I will not go into details here. Interested readers can refer to the relevant information further.

There are two ways to arrange the line of the RJ-45 connector, 568b and 568a, we commonly use 568b method, see:

In fact, in the 10 m network, only 12 36 lines are used, and the M network needs all.
The two sides use the same standard line as the direct connection line, which is used to connect a PC to a hub common port and a hub-level connection port.
The two sides use a line that is not the same as the standard, called a cascade line, used for connecting a PC to a PC and a hub common port to a hub common port.
Unpredictable packet loss occurs when the lines that do not follow the standard arrangement are working at MB.
The reason for the above packet loss is that the line-to-line interference is too large. If you do not remember the standard, at least 12 36 lines should be twisted together, because they are a pair of differential drivers.
Follow the EIA/TIA 568b standards to create connectors. According to the figure, the line pairs are arranged in a certain color order (1, white orange, 2, orange, 3, white green, 4, Blue, 5, white blue, 6, green, 7. White Brown, 8, brown ). Note that the Green Line must span the blue line. The easiest thing to make mistakes here is to put the white green line and the green line together, which will cause crosstalk and reduce transmission efficiency. After the cables are properly arranged, cut the exposed twisted pair wires with special pliers, with only about 15mm length left, and pin the wires together, put each line of the twisted pair into the pin of the RJ45 connector in sequence. The first pin should be white-orange lines, and so on ..

After you confirm that each wire of the twisted pair has been correctly placed, you can use RJ45 crimping pliers to contract the RJ45 connector. Because the NIC is directly connected to the hub, the pin connection method of the RJ45 connector on the other end is the same. After completion, the RJ45 connectors at both ends of the connection line must be completely consistent.
Finally, test it with a tester. So the RJ-45 head is made.
When connecting to a hub-level connection (or connecting to a PC using a PCL), you should place the control switch of the level-level connection port on the MDI (uplink ).
Use a direct connection. You must use
MDI-X port level connection, at this time, we can cross line to achieve the goal, here the cross line, that is, when doing network cable, with one end of the RJ-45 plug 1 foot to the other end of the RJ-45 plug 3 foot; then use one end of the RJ-45 plug 2 feet to the other end of the RJ-45 plug 6 feet. It can be prepared by the following Chromatography:
End A: 1 orange white, 2 orange, 3 green white, 4 blue, 5 blue white, 6 Green, 7 brown white, 8 Brown;
End B: 1 green white, 2 green, 3 orange white, 4 blue, 5 blue white, 6 orange, 7 brown white, 8 Brown