The term serial port may not be understood by many people who are not engaged in computer-related industries. It is generally called COM interface. As the name implies, it is an extended interface that uses serial communication. It can reduce costs and is especially suitable for some long-distance communications. But the transmission speed is relatively slow.
1. What is a serial port card
Serial card is the abbreviation of multi-serial card. Of course, it can also be called a serial expansion card. Most of them are key accessories of a multi-user communication control system used in fields such as securities, wires, banks, finance, and industrial control. A multi-serial port card is a device that can allocate multiple serial/parallel ports for terminal connection, and each terminal can communicate with the host computer through it.
Here is an introduction to what a serial port is. The serial ports referred to here are RS232, RS422 and RS485. Other serial ports such as SATA are not included. The parallel port is PARALLE PORT, which is a 25-pin parallel interface, also called a printer interface.
2. Serial port card type
There are two types of multi-serial port cards, one type is inserted in the PCI or PCI-E, USB slot, and can expand 1~4 com ports. After assembling the driver, you can see com3, com4, etc. in the device manager . There is another one that is connected to the network, allowing several computers to share the above com port resources, but the configuration is a little troublesome.
It is especially suitable for multi-client control systems such as UNIX and liunx, and it is also suitable for operating environments such as WINDOWS95/98/2000, WINDOWSNT, DOS, etc. The chip solutions sold abroad are basically applicable to WINDOWSXP/2003/Vista/Win7 . Multi-port cards are widely used in banking, finance, securities, telecommunications, industrial control and other fields, and are an important hardware component of computer multi-client communication control systems.
3. How to expand the serial port card of the industrial computer
1. PCI expansion
So how does the industrial computer expand the serial port card? First, expand through the PCI expansion slot on the industrial computer,
2. PCI-E expansion
How can the industrial computer expand the serial port card? It can be expanded through the PCI-E expansion slot on the industrial computer, as shown in the figure:
PCI-E can not only extend the RS485-2 serial port card, but also can expand the RS232-4 serial port card. It is mainly to choose different serial port cards according to the requirements of customers.
4. Differences between RS-232 and RS-485 interfaces
1. RS-232 interface
One of the computer communication interfaces, usually the RS-232 interface appears in the form of 9 pins (DB-9) or 25 pins (DB-25). Generally, there are two sets of RS-232 interfaces on a personal computer. They are called COM1 and COM2 respectively.
2. RS-485
RS485 has no specific physical shape and is an interface adopted according to the actual situation of the project.
In summary, these are probably related to the expansion of the serial card by the industrial computer through the PCI or PCI-E expansion slot, involving the meaning of the serial card, the type of the serial card, how the industrial computer expands the serial card, and RS-232 and RS-485 I hope you have a deeper understanding of how to expand the serial port card of the industrial computer.
