Overview of Industrial Switch Interface Types

As a necessary product in the industrial field, industrial switches also exist in the wide area network, but we usually rarely see such industrial switches, so here we mainly take our common LAN industrial switches as  an example to introduce various interfaces of industrial switches. and connection method.In the local area network, the industrial switch is used as the centralized connection device of the local area network. By studying the main network types of the local area network and the development process of the transmission medium, we have concluded that there are about the following five interface typesof industrial switch: 1. Twisted pair RJ-45 interface, 2. Optical fiber Interface, 3. AUI interface and BNC, 4. Console interface, 5. FDDI interface.

1. Twisted pair RJ-45 interface

This is the most widely used interface type we have seen, and it 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 current mainstream 100Base-TX Fast Ethernet and 1000Base-TX Gigabit Ethernet. Although the transmission media they use are all twisted pair types, they each use different versions of twisted pair types, such as the original 10Base-T Category 3 cable to the Category 6 cable that supports 1000Base-TX Gigabit rates , the middle 100Base-TX uses the so-called Category 5 and Super Category 5 cables, of course, it can also be Category 6 cables. The appearance of these RJ-45 connectors is exactly the same, like a flat "T". Connected to it is an RJ-45 crystal head, a crystal head and a twisted pair network cable for connecting the crystal head.

2. Optical fiber interface

For the transmission medium of optical fiber, although this transmission medium has been used as early as the 100Base era, this 100M network was called "100Base-TX" in order to distinguish it from the commonly used 100M Twisted Pair Ethernet 100Base-TX. FX", where "F" is the first letter of "Fiber". However, at the time of 100 Mbps, compared with the traditional twisted pair medium, the advantages were not obvious, and the price was much more expensive than the twisted pair, so the optical fiber was not widely used in the 100Mbps era. It is mainly from 1000Base It has been fully applied since the technology was officially implemented, because at this rate, although there are twisted pair media solutions, the performance is far less than that of optical fibers, and it has obvious advantages in connection distance, which is very suitable for metropolitan area networks and wide area networks. use.

At present, the development of optical fiber transmission media is quite rapid, and various optical fiber interfaces are emerging in an endless stream. However, in the industrial switch of LAN, the optical fiber interface is mainly SC type, whether it is in 100Base-FX or 1000Base-FX network. The core of the SC interface is in the connector, which is an SC optical fiber interface module for 100Base-FX network, and an optical fiber industrial switch that provides 4 SC optical fiber interfaces.

From the appearance of the SC interface of the industrial switch, it can be seen 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 the type of contact chip. If it is 8 copper shrapnel, it is an RJ-45 interface, and if it is a copper column, it is an SC fiber interface.

3. AUI interface and BNC

The AUI interface is specially used to connect thick coaxial cables. Although this kind of network is rare in local area networks, in some large enterprise networks, there may still be some legacy thick coaxial cable token network devices. Therefore, some industrial switches also retain a few AUI interfaces to meet user needs to the greatest extent. The AUI connector is a 15-pin "D" shaped connector, similar to a monitor connector. This kind of interface is also seen in many network devices, such as routers and even servers, and the schematic diagram of the AUI interface on the router.

BNC is an interface specially used to connect with thin coaxial cable. Currently, industrial switches that provide this interface are relatively rare. However, a few BNC interfaces are also provided in some RJ-45 Ethernet industrial switches and hubs, which are specially used for token network connections with thin coaxial cables as the transmission medium.

4. Console interface

We know that this interface is used to configure industrial switches, so only managed industrial switches have it. Also, note that not all managed industrial switches have it, because there are many ways to configure industrial switches, such as Telnet command line, Web, and TFTP. Although theoretically, the basic configuration of the industrial switch must be done through the Console (control) port, but the basic configuration of some brands of industrial switches is already configured at the factory, and there is no need for basic configuration such as IP address and basic user name. Therefore, this type of managed industrial switch does not need to provide this Console interface, and it still accounts for the majority at present. This type of industrial switch usually only needs some advanced configuration through simple Telnet or Java program Web.

Of course, some industrial switches still provide console ports, but it should be noted that the console ports used for configuration of industrial switches are not the same for all industrial switches, and some use the same RJ-45 type console ports as Cisco routers. And some use the serial port as the Console interface.

The console ports of the two industrial switches are different, a "female" 9-hole "D"-shaped interface, and a "male" 9-pin "D"-shaped interface. They are commonly known as "DB-9" interfaces, but they are all used for industrial switch configuration.

In addition to the above two console ports of industrial switches, there is another interface that is also commonly used in the configuration of industrial switches, that is, the 25-pin "D" interface.

Regardless of whether the industrial switch adopts the DB-9 or DB-25 serial interface, or uses the RJ-45 interface, when configuring the industrial switch, it is generally necessary to connect to the serial port of the configuration computer (usually called the terminal) through a special Console cable. Line port, compatible with different Console ports of industrial switches. There are also two types of console lines, one is serial line, that is, both ends are serial interfaces (both ends are female or one end is male, the other end is female), both ends can be inserted into the computer respectively The serial port and the Console port of the industrial switch; the other is a flat cable with RJ-45 connectors (RJ-45-to-RJ-45) at both ends. Since both ends of the flat cable are RJ-45 interfaces, they cannot be directly connected to 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. . Usually, such a Console cable and the corresponding DB-9 or DB-25 adapter are randomly presented in the box of the industrial switch.

5. FDDI interface

In the early 100Mbps era, there was also an FDDI network type whose Chinese name was "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.

The above five types are the interface types of some common industrial switches. Of course, there will be some uncommon interface types, such as the ATM network interface, and the type of optical fiber network interface is far more than SC, but in the enterprise LAN industrial switch, these interfaces are difficult to meet, so I will not introduce them here.