Introduction to the Simple Identification Method of Fake Network Cable

There are mainly two types of network cables used in computer LANs: twisted pair and coaxial cables. Among them, coaxial cables have been basically eliminated, and a large number of twisted pairs have been used.

Twisted pair is divided into shielded twisted pair (STP) and unshielded twisted pair (UTP). Because STP is only used in some special occasions (such as severe electromagnetic interference, susceptibility to chemical corrosion, etc.), the following mainly introduces the identification method of true and false UTP.

Determine the type of twisted pair

The wires in the twisted-pair cable appear in pairs, each pair is a pair, and twisted around each other. According to the American Wire and Cable Specification (AWG): all the wires in a twisted pair should be 4 pairs, a total of 8 wires. However, the 10M Ethernet standard stipulates that only 2 pairs of wires are used to transmit signals, so some of the category 3 twisted pairs are 2 pairs, and some are 4 pairs.

The emergence of Fast Ethernet, on the one hand, theoretically increased the speed of the original 10M network by 10 times in theory, on the other hand, prepared for a faster network in the future (Gigabit Ethernet, transmission speed of 1000Mbps), and transmitted Category 5 twisted pair with a speed of 100Mbps is also in use. Although Fast Ethernet only uses 2 of them, Gigabit Ethernet must use all 4 pairs.

It is recommended that you take a look at the labels on the network cable. For example, the words marked "CAT3" are generally Category 3 wires. When the words marked "CAT5" are shown, they are Category 5 twisted pairs.

Actually test its speed

Now the established network generally uses twisted pairs of category 5 or above, and category 3 twisted pairs have been eliminated. However, some manufacturers of twisted-pair cables encapsulated the conductors originally used for Category 3 cables in cables printed with Category 5 twisted-pair cables after the introduction of Category 5 twisted-pair standards. When you use this kind of fake Category 5 cable, the actual communication speed of the network can only reach 100Mbps specified by Category 5 twisted pair within a short distance.

This kind of fraud is very hidden, and it is difficult for ordinary users to find out. At this time, it is recommended that you first buy a paragraph and use the "System Monitor" in Windows 98 or the "Network Monitor" in Windows NT Server 4.0 to test it yourself. If the test speed reaches 100Mbps, it indicates that it is Category 5 twisted pair.

If there is only 10Mbps, it means that Category 3 wire is used in the cable. This method can not only correctly distinguish category 3 and category 5 wires, but also can be used to test whether the twist degree of each pair of wires in a twisted pair cable meets the standard, and can also determine whether the metal medium in the wires is qualified. Please note: When performing network speed tests, the length of the twisted pair should be the standard length of 100 meters, otherwise the measured data has no practical significance.

Believe your own eyes

Not all network wiring is concentrated in an air-conditioned office, so the network cable must have certain properties such as heat resistance, tensile strength, and flexibility: first, you can test the twisted pair in a high temperature environment, really When the ambient temperature of the twisted pair reaches 35 ℃ to 40 ℃, the outer layer of rubber will not become soft, but the false one will.

In order to ensure the safety of the connection, the rubber sheath of the real twisted pair cable has strong tensile resistance, but the false one does not; the copper metal is generally used in the twisted pair cable, and some manufacturers in order to reduce costs during production, in Other metal elements are added to the copper. Its intuitive performance is that the adulterated wire is obviously harder than normal and is not easy to bend. It is easy to break the wire during use.

The rubber outside the real twisted pair is also flame resistant, while the fake one is made of ordinary flammable materials, you can try it yourself when you buy it; when you need to use shielded twisted pair, you should pay attention to the shielded twisted pair It is very different from the unshielded twisted pair that we commonly use. Compared with unshielded twisted-pair wire, a layer of metal mesh and a thin layer of insulating material are added between the shielded twisted-pair wire and the outer rubber, and the outside of the corresponding crystal head is wrapped with metal.