Serial Networking Device Server Introduction

Date：2009-08-02 Author：Shanghai ZLAN Views：5145

Abstract：this paper introduces the definition, origin, application industry and usage of serial port networking server.

Serial port networking server is an interface conversion device of serial port connecting to the network, due to the serial port generally includes RS422/232/485, the network protocol also refers to the TCP/IP protocol, so the serial port networking server also be as a communication interface converter of converting RS422/232/485 data form into TCP/IP data form or converting TCP/IP data into RS422/232/485 data form.

The following is a series of serial device servers in Shanghai ZLAN information technology:

For serial port networking servers, two key words are serial port and network. The network is divided into two types: Intranet and extranet. Currently, Intranet refers to Ethernet, and the external network refers to the Internet, which is an effective means of communicating globally. Before the popularity of the Internet, the exchange of data between the device and the computer was realized through simple RS232. RS485 (up to 1000 meters) can also be used if remote transmission is required.

With the development of network and modern information technology, several requirements for device are gradually raised:
1). Some applications require remote monitoring of devices distributed around the world.
2). In the applications like the computer room monitoring, self-service banking system communication, building automatic control system and so on, itself has the complete network cabling, can use the existing communication network infrastructure to realize the device communication.
3). For RS232 interface, a serial port of PC can only connect one serial port device. If multiple devices need to be connected, the original serial port scheme will not be easy to expand, and the network will not have the problem.

For the above reasons, you need to connect the device to the network. But there have been hundreds of thousands of original serial device exists, large quantities of transformation of these devices is clearly not happen overnight, thus as a temporary solution, the serial port networking server of serial port to Ethernet port was born.

The serial port network server is currently applied to: access control attendance system, POS system, rice selling system, building automation system, power monitoring, self-service banking system, telecom computer room monitoring, etc.

After getting a serial port networking server: 1). Wired: first of all connect the serial port of serial port networking server with the serial port device, the RJ45 of serial port networking server connect with router (or directly PC with cross wire), and then put the serial port networking server power on.
2). Configure serial port parameters: the parameters of serial port networking server can be modified by using the computer tool or Web page. The main difference between these two approaches is that the serial port networking server must be in the same subnet as the computer when modifying parameters through a Web page. The serial port parameters generally include: baud rate, data bits, stop bits, check bits.
3). Configure network parameters: the serial port networking server must have an IP that can be configured to be static or obtained through the DHCP server. Configure the working mode of serial port networking server: including TCP server mode, TCP client mode, UDP mode. The server-side mode refers to the computer actively looking for the serial port networking server; The client mode refers to the serial port networking server actively looking for the computer. The purpose of configuring network parameters is to enable the computer to successfully connect to the networking server.
4). Enable virtual serial port: due to the general user's PC software open the serial port to communicate with device, so at this time due to modifying the network it must create a virtual serial port on the computer (the own software of the serial port networking server can create virtual serial port), the virtual serial port is responsible for establishing connection with serial port networking server, and forward the data to the user program with opened the virtual serial port.
5). Run the user device communication program and open the virtual serial port. The user application then communicates with the device.