How do I check network cables?check network cables

1. Because it was connected to the Internet normally, and it still cannot be connected after restarting the router, it is necessary to judge whether it is a problem of poor network cable contact.

2. There are a total of eight cables in the network cable, of which cables 1, 2, 3, and 6 are mainly responsible for data transmission, and the corresponding cable colors are white-orange, orange, white-green, and green.

3. First, use the line tester to check whether the 1, 2, 3, and 6 cables of the network cable are connected. If they are connected, there will be a green light on the line tester.

4. If the 1, 2, 3, and 6 cables have one or two green lights on the line tester that do not light up, do not directly judge the network cable.

5. If the 1 or 3 cable is not lit, you can exchange it with the 7 cable, and then redo the crystal head (both ends of the network cable must be re-exchanged), and then use the line tester to measure and see if it is replaced to the 7 position. The 1 or 3 cable will not light green.

6. If the 2 or 6 cable does not light up, swap it with the 8 cable, then redo the crystal head, and then use the line tester to see if the green light of the cable replaced to the 8 position will be on.

7. After the exchange, you may find that the 1, 3 or 2, 6 cables that were not bright before are bright, and you can judge that the network cable is not broken in the middle. Through this method of exchanging the network cable, the two situations of poor network cable contact and failure to make the crystal head can be excluded. If the green light is on after the cable is tested by the cable tester, it means that the network cable can be connected normally. , you can avoid spending a lot of time re-pulling the network cable.

When there is a problem with the line in the network, how do we analyze and troubleshoot it?

Problem 1: The RJ45 connector of the network cable is loose, resulting in poor contact.

This kind of problem is the most common problem. Due to the frequent plugging and unplugging of the network cable, the quality of the network cable is poor, and the problem of the crystal head production process. Therefore, the normal network cable is used for a long time, and there will be poor contact. affect the Internet.

Fault phenomenon:

In the case of excluding the disconnection of the network cable itself, when using the line measuring instrument to measure the line, the performance is as follows: some indicator lights do not light up

Solution:

Rework the problematic crystal head.

Problem 2: The metal antennae on the RJ45 connector are oxidized and dusted, resulting in poor contact.

This type of problem is mainly prone to occur in a humid environment, and the metal antenna on the crystal head is oxidized by the air or covered by dust, resulting in poor contact. Of course, it also has a certain relationship with the quality of the crystal head itself.

Fault phenomenon:

By eye observation, see if the metal tentacles on the crystal head are blackened, or there is a lot of dust; further test with the help of a line measuring instrument.

Solution:

Rework the problematic crystal head.

Question 3: The RJ45 line sequence is incorrect.

There are certain standards and specifications for the production of crystal heads, and it is best to make them in strict accordance with the standards and specifications.

The standards are as follows:

568A: White Green | Green | White Orange | Blue | White Blue | Orange | White Brown | Brown

568B: White Orange | Orange | White Green | Blue | White Blue | Green | White Brown | Brown

Usually, both ends of the network cable will be made according to the 568B standard, which is commonly known as a straight-through cable;

Crossover cable: one end is 568A, the other end is 568B, both are used less now.

Fault phenomenon:

When testing through the line tester, the light sequence of the indicators at both ends of the line tester is crossed (only for straight-through lines)

Solution:

Rework the problematic crystal head.

Question 4: The metal antenna of the RJ45 connector is short-circuited.

This type of problem is relatively rare and difficult to find out, and often occurs on some low-quality crystal heads.

Fault phenomenon:

When using the line measuring instrument to measure the line, the performance is as follows: some indicator lights on the line measuring instrument flash at the same time.

Solution:

Rework the problematic crystal head.

Question 5: Some cores of the network cable are disconnected.

How to troubleshoot:

Through the test of the line measuring instrument, under the premise of eliminating the problem of the crystal head itself, which cores are not bright, the corresponding cores may be broken.

Solution:

For a 100M link, you only need to ensure that there are 4 cores in the network cable; for a 1000M link, you can only re-wire.