Failure Analysis of twisted pair cabling with non-abrupt View Details

So how to master the quality of these media to ensure smooth transmission of information, you need to rely on the verification of the Cable Testing Instrument. In addition, more than 90% of the network faults are caused by cable link problems, but these problems can not be checked in the shortest time only by visual or multimeter. During network construction, you must test the cable using a regular tester.

In general, the network card will not strike easily, most of which are network faults caused by incorrect settings and hardware connections. When checking for network faults, You can generally start with the system's network settings (mainly to check the IP address, DNS, and whether the gateway is incorrect or lost), and then check the physical connection. There will be many specific faults, such as: whether the twisted pair wires are good, whether the twisted pair wires are broken, and whether the hub slots are easy to use (try another slot ).

In the Cabling Process of twisted pair wires, it is easy to see the line sequence problem that the network is "connected" but "disconnected. Many users often use a one-to-one error connection method in cabling. When the connection distance is short, the system will not encounter connection faults. However, when the connection distance is long, the network is busy or high-speed, it is easy ......, The core is to make the 3 and 6 pins the same twisted pair (based on the T568A or T568B standard ). The distance between a user server and a vswitch is changed from 5 meters to 60 meters. The connection fails no matter what the connection method is. Why? In Ethernet, two pairs of twisted pair wires are usually arranged at the positions of 1, 2, 3, and 6. If not, instead, the cables used by the original matching pairs are used separately to form a crosstalk (SplitPair errors refer to the transmission performance faults caused by SplitPair errors that are not correctly installed during cabling ), it has a great impact on network performance. The 10 m network environment is not obvious. In a m network environment, if the traffic is large or the distance is long, the network cannot be connected. This is the reason for the above phenomenon. As the pairing line is not used in 3 and 6, there is no problem in the case of short distance. However, once the distance gets longer, the fault will occur. You only need to repeat the RJ45 header in line order to restore everything to normal. In addition, several twisted pair cable manufacturers, in order to better meet the performance standards of twisted pair wires, two pairs of twisted pair wires have a higher degree of winding than the other two pairs, of course it is standard orange, orange white and green white, so it is best to use them for 1, 2, 3, 6.

Therefore, in the network construction process, after the Integrated Wiring is completed, the twisted pair wires should be tested. The test of unshielded twisted pair wires for structured cabling can be divided into on-going testing and certification testing. The on-going test focuses on the connection performance of structured cabling, and does not care about the electrical characteristics of structured cabling. This ensures that all connections are correct. Certification testing refers to testing the structured cabling system in accordance with the standards to determine whether all structured cabling meets the design requirements.

Generally, the channel performance of Structured Cabling depends not only on the construction process of cabling, but also on the quality of the cables used and related connection hardware. Therefore, you must perform authentication tests on structured cabling, also known as 5-class test certification. By testing, you can confirm whether the installed cables, related connection hardware and their processes meet the design requirements, including connection performance testing and electrical performance testing. Cable installation is mainly based on the installation process. Since no one can work correctly, we must conduct link testing to ensure that the installation of cables meets the performance and quality requirements. If no test tool is available, connection errors may occur. Common connection errors include cable label errors, open connections, and short circuits.

In the construction of open and short circuits, open or short-circuit faults may occur due to problems such as lack of tools, wiring skills, or wall Threading Technology.

The same pair of wires are uplinked at both ends. For example, one end is 1-2, and the other end is 2-1.

An error occurs when a line is connected to another line at the other end. For example, one line is 1-2, and the other end is connected to 4-5.

The so-called string winding refers to splitting the original two pairs and then forming a new line pair. As the connectivity of the end-to-end is not affected when such a fault occurs, the common multimeter cannot be used to check the cause of the fault. Only a dedicated cable tester can be used to check the cause.

The certification test does not improve the channel performance of the integrated wiring, but only confirms whether the installed cables, related connection hardware and their processes meet the design requirements. The result is valid only when a testing instrument that meets specific requirements is used and tested according to the corresponding testing method. For example, Pentascanner5 class tester is used for 5 class tests. The method is: First connect the two ends of the Jumper with the tester, then test by AutoTEST, then display the test results by F1, and finally print the test results.

The following problems occur during the test:

◆ The cause of the failure of the close-end crosstalk may be the problem of the close-end connection point, or because of the performance problems of the series, external interference, remote connection point short-circuit, link cable and connection hardware, not the same type of products and cable, and so on.

◆ The failure of the wiring diagram may be caused by an open circuit, short circuit, cross or broken connection at both ends, or a cross-connection error.

◆ The cause of failure in attenuation may be that the cable is too long, the temperature is too high, or the connection point is faulty. It may also be the performance problem of The Link cable and connection hardware, or it is not the same type of product, there may also be problems with the quality of the end-to-end cables.

◆ Failure in length may be caused by long cables, open or short circuits, or long connections between devices and cross-wiring.

◆ The fault of the tester may be caused by the tester not being started (The problem can be solved by replacing the battery or charging) tester cannot work or remote calibration, tester is set to incorrect cable type, tester is set to incorrect link structure, tester cannot store automatic test results and tester cannot print Storage automatic Test results.

1. Network twisted pair Cable troubleshooting instance
2. Common wiring system faults and troubleshooting Technology