Today, many devices use serial communication, especially in industrial automation and security monitoring projects. The biggest advantage of serial communication micro bluetooth module is that it is convenient to plug and play, and it is more common. Moreover, serial communication has the disadvantages of short distance and slow transmission rate.However, with the rapid development of today's science and technology, a large amount of information and communication data increases, and the requirements for distance are also increasing. It is important to implement remote control and other requirements where serial ports must be tightly connected with Ethernet or fiber optic communications.Therefore, with the development of the times and the advancement of technology, equipment that converts serial signals into Ethernet signals has emerged: from RS232\/485 to RJ45 serial servers. From serial port to network port and from network port to serial port, because these products can convert both ways, it is actually the same.Serial to Ethernet ConversionIt is not a simple conversion between the physical layer and the data link layer. Since the serial port protocol itself has no network layer and transport layer, the data to the Ethernet serial port actually uses the serial port data as TCP\/IP application layer data, and uses the TCP\/IP packet forwarding method. For example, the user passes The recv() function and send() function of the socket send and receive data that is actually the application layer. This allows the user to send and receive serial data to and from TCPIP over the serial port using the recv() and send() functions. However, TCP\/IP is as simple as recv() and send(). Depending on the action mode, it is related to connection, shutdown, monitoring, etc. This is the part that needs to be dealt with after converting the serial port to a network port.