1. Twisted pair RJ-45 interface

This is the most common and widely used interface type, which belongs to the twisted pair Ethernet interface type. It is not only used in the most basic 10Base-T Ethernet network, but also in the mainstream 100base TX Fast Ethernet and 1000base TX Gigabit Ethernet. Although the transmission media they use are all twisted pair types, they use different versions of twisted pair types. For example, the class-3 line used in the initial 10Base-T to the class-6 line supporting 1000base TX Gigabit rate, and the so-called Class-5 and super Class-5 line are used in the middle 100base TX. of course, it can also be class-6 line. The appearance of these RJ-45 interfaces is exactly the same, like a flat “t”. Connected with it is the RJ-45 crystal head, a crystal head and a twisted pair network cable for connecting the crystal head. It is a 24 port RJ-45 Ethernet industrial switch, including two SC optical fiber interfaces and one AUI interface.

2. Optical fiber interface

As for the optical fiber, this kind of transmission medium has been used as early as the 100base era. At that time, in order to distinguish it from the commonly used 100base TX, this kind of network was called “100base FX”, in which “F” is the first letter of “fiber”. However, at that time, compared with the traditional twisted pair medium, the advantage was not obvious, and the price was much more expensive than twisted pair, so the optical fiber was not widely used in the 100Mbps era. It was mainly used since the formal implementation of 1000base technology, because at this rate, although there were twisted pair medium solutions, the performance was far inferior Optical fiber is good and has obvious advantages in connection distance. It is very suitable for man and WAN.

At present, the development of optical fiber transmission media is quite rapid, and all kinds of optical fiber interfaces are not studied. However, in LAN industrial switches, the optical fiber interface is mainly SC type, whether in 100base FX or 1000base FX network. The core of SC interface is in the connector, a SC optical fiber interface module of 100base FX network, and an optical fiber industrial switch with four SC optical fiber interfaces.

It can be seen from the appearance of the SC interface of the industrial switch that it is very similar to the RJ-45 interface, but the SC interface seems to be flatter and the gap is shallower. It mainly depends on what type of contact chip is. If it is 8 copper shrapnel, it is RJ-45 interface. If it is a copper column, it is SC optical fiber interface.

3. AUI interface and BNC

AUI interface is specially used to connect thick coaxial cable. Although this kind of network is rare in LAN, in some large enterprise networks, there may still be some left over thick coaxial cable token network equipment, so some industrial switches also retain a few AUI interfaces to meet the needs of users to a greater extent. The AUI interface is a 15 pin “d” interface, similar to the display interface. This kind of interface is also seen in many network devices, such as routers, and even servers, the schematic diagram of AUI interface on routers.

BNC is an interface specially used for connecting with thin coaxial cable. At present, there are few industrial switches providing this kind of interface. However, in some RJ-45 Ethernet industrial switches and hubs, a few BNC interfaces are provided, which are specially used for token network connection with thin coaxial cable as transmission medium. In order to show you the real appearance of BNC, the following BNC interface network card to show you.

4. Console interface

As we know, this interface is used to configure industrial switches, so it is only available for network management industrial switches. It should also be noted that not all network management industrial switches are available, because there are many configuration methods for industrial switches, such as telnet command line mode, web mode, TFTP mode, etc. Although in theory, the basic configuration of industrial switches must be through the console port, the basic configuration of some brands of industrial switches has been configured at the factory, and there is no need to carry out the basic configuration such as IP address and basic user name. Therefore, this kind of network management industrial switches do not need to provide the console interface, and it still occupies a large proportion at present most. This kind of industrial switch usually only needs some advanced configuration through simple telnet or Java program web.

Of course, some industrial switches provide console interface, but it should be noted that the console port used for industrial switch configuration is not the same for all industrial switches, and some use RJ-45 type console interface similar to Cisco router. Some use serial port as console interface.

The console ports of the two industrial switches are different, with a female 9-hole “d” interface and a male 9-pin “d” interface. They are commonly known as “DB-9” interfaces, but they are all configured with industrial switches.

In addition to the above two console ports of industrial switches, another interface is also commonly used in the configuration of industrial switches, which is the 25 pin “d” interface.

Whether the industrial switch adopts DB-9 or db-25 serial interface or RJ-45 interface, when configuring the industrial switch, it generally needs to connect to the serial port of the configuration computer (usually called the terminal) through a special console cable, which is suitable for different console ports of the industrial switch. The console cable is also divided into two types, one is serial cable, that is, both ends are serial interfaces (both ends are female or one end is male and the other end is female), and both ends can be inserted into the serial port of the computer and the console port of the industrial switch respectively; the other is flat cable with RJ-45 connector (rj-45-to-rj-45) at both ends. Since both ends of the flat line are RJ-45 interfaces, it is impossible to directly connect with the computer serial port. Therefore, an rj-45-to-db-9 (or rj-45-to-db-25) adapter must be used at the same time. Normally, such a console line and the corresponding DB-9 or db-25 adapter will be presented randomly in the packaging box of industrial switch.

5. FDDI interface

In the early 100Mbps era, there was another FDDI network type, its Chinese name was “optical fiber distributed data interface”. Obviously, its transmission medium was also optical fiber, and its interface type was mainly SC type. At present, because its advantages are not obvious, it is basically gone.

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