Now the Internet has become a necessity of life, mobile phones, computers, even TV, without the Internet would be a lot less fun and attractive, then, as the "bridge" of Internet operation ---- network cable, is indeed something we need every day.

A little knowledge about the network cable, today and share with you.

Network cable is a cable inserted into the network card, such as home broadband, optical cat and router is connected by network cable.

As shown in the picture below, this blue cable is the Internet cable.

1 Concept of Network cables

Devices to send and receive a variety of information, rely on the transmission medium to transmit information, the signal transmission between the network equipment cable, known as the network cable, referred to as the network cable, we usually contact the most twisted pair.

2 Classification of network cables

The categories are as follows:

1000BASE-T means that the bandwidth transmission capacity is 1000Mbps, and all 8 cores are used, which is the most commonly used cable at present. The figure is only an early classification, and there are 6 types and 7 types of network cables not listed.

Twisted Pair (TP: Twisted Pairwire) can be divided into Unshilded Twisted Pair (UTP: Unshilded Twisted Pair) and Shielded twisted pair (STP: Shielded Twisted Pair). The UTP line is the one that is touched more.

A twisted pair is a cable composed of eight wire cores that are wound together according to certain rules. Twining in pairs is to reduce electromagnetic interference.

The magnetic field will be generated around the energized conductor, and the current is periodically changed, resulting in other wires in this magnetic field will produce other currents that are not needed, affecting the transmission of normal signals by the cable. Due to the different division of labor of each wire, the direction of the current is not the same, and the cables in the opposite direction of the current are wound together. This will minimize interference.

The shielding layer is also added to reduce external electromagnetic interference.

Application scenario of shielded cables: It is recommended that shielded cables be used to connect devices in complex environments, such as medical devices.

3-wire sequence

There are two standards for line sequence, 568A and 568B:

568A Line sequence: Green white, green, orange white, blue, blue white, orange, brown white, brown.

568B line sequence: Orange white, orange, green white, blue, blue white, green, brown white, brown.

Straight connection: Both ends of the RJ45 connector must be in the same cable sequence, that is, both ends are in the 568A or 568B cable sequence.

According to the theory, which line sequence can be used, but because everyone is using the 568B line sequence, the network cable can also be done manually, and the use of two wire sequences at the same time is easy to produce confusion, so the unified use of 568B, remember the 568B wire sequence.

Cross line: One side is the 568A wire sequence, one is the 568B line sequence, such a line is the cross wire.

4. Relationship between two wire sequences

As shown below:

568A and 568B 1 and 3 interconnects, 2 and 6 interconnects, where each foot is defined:

1 Output data (+)

2. Output data (-)

3. Enter data (+)

4. Reserve for phone use

5. Reserve for phone use

6. Enter data (-)

7. Reserve for phone use

8. Reserve for phone use

This is the definition of a 100-megabit line interface, and later because the phone does not use the cable to transmit directly, it uses network data to transmit telephone signals, and uses VoIP phones, and IP-based Voice transmission (English: Voice over Internet Protocol, abbreviated as VoIP) 8 wires are all used for network transmission.

This connection means that my output is your input and my input is your output.

In this way, you can analyze the use scenario of this kind of wire, if two plugs or two sockets, it must not be plugged together. You need one plug and one socket.

According to this understanding, in the early days, equipment was divided into similar devices and different types of equipment.

This is a picture of my device that I found in the company's warehouse. Below is a Cisco Catalyst 3750 switch:

The X in this interface has a special meaning:

Cross cables are used between X and X. Here is a picture I took on a Cisco 2690 router:

This device interface does not have that X, that is, those with X and those without X use a straight-through wire.

Therefore, Cisco products a total of two categories, with X and without X, the same kind of cross line, different kind is through wire.

This is an early product, but later the device supports self-adaptation to the line sequence, so it is no longer necessary to distinguish which line should be used between the devices, and the line is all used through the wire, which is convenient for memory and convenient for production.

Aichie Tech has always been in a leading position in the R&D and production of wire and cable. The company's cable products have obtained UL certification for many times, and have been widely recognized and used around the world. The company's wire and cable products include electronic wires, automotive wires, medical cables, industrial control cables, silicone wires, high-voltage cables, energy storage cables, new energy charging cables and other wires, which are widely used in automobiles, industries, construction, medical, subway, robot, motors Servo system and other fields.

If you have any needs about wire and cable, you can contact Dongguan Aichie Tech Electronics Co Ltd., we will provide high-quality wire and cable products to meet customer needs.E-mail: sales03@aichie.com