Serial server transparent transmission principle

The serial port server is a small electronic device that performs two-way transmission between TCP/IP data and serial port data. Its working principle is that when the serial port server is connected to the computer, it will create a virtual COM port in the computer’s device manager, and send TCP/TP data packets through the COM port to the network through the serial port data connected by the internal circuit. If the serial port sends 010110, the network end also receives the data of 010110, and there will be no protocol in the middle for processing. What are the common serial ports?

Common serial interface definitions

● RS232: Interface for exchanging serial binary data between two devices.

● RS485: An interface used to exchange serial binary data between serial devices. Compared with RS232, it supports multi-point two-way communication. During communication, it supports multiple terminal devices to be linked to the same serial port.

● RS422: An interface used to exchange serial binary data between serial devices. Compared with RS232, RS422 provides faster transmission rate and longer transmission distance. (The maximum transmission rate decreases with cable length. The transmission rate at 12 meters is about 10 Mbit/ s, and at 1200 meters the transmission rate drops to 90 kbit/s). RS485 expands the interface application of RS422.

● TTL: TTL is a serial port form of serial port to Ethernet. The above three are the serial port forms of the device side.

● X.21: An interface for exchanging signals between data terminal equipment (DTE), such as user computers, and digital data circuit terminal equipment (DCE).

● V.24: An interface that supports both synchronous and asynchronous transmission modes. When operating in asynchronous mode, the V.24 interface functions similarly to the RS-232 interface.

● V.35: It is a universal terminal interface standardized by ITU-T for telephone network transmission. The interface was originally a modem interface standard that used the bandwidth of multiple 60-108 kHz basic telephone circuits as a group to transmit synchronized data at 48 kbit/s. Currently, V.35 is mainly used for Nx64 kbit/s data interface and has been replaced by V.36 interface. However, the V.36 interface is still called the V.35 interface.

Advantages of using serial port server for networking

Using a serial port to connect a computer to a serial device is simpler and more reliable. When using a serial port, there is no need to install a network card or set an IP address to achieve networking.

Using a serial port server for networking not only ensures stable transmission, but also reduces network construction costs. There is no need to use dedicated lines, and multiple serial port devices can be run on a single network port on the computer.