Modbus Serial (ACII/RTU) OPC Server 320 was developed by OPCTechs Technology Corporation in June 2005. According to the standard OPC 3.0 Specification, we developed the packaged software for our extended customers especially in the automation fields. It is suitable in the integration fields in every walk of life. Modbus protocol is one of the most popular communication protocols in the world today. As the new devices create, the device makers should embed the modbus protocol. Modbus protocol let the engineers fast and easily to integrate devices to the automation software. The devices such as power meter, water leakage machine, generator, and UPS. They all inborn provide the Modbus communication protocol. This version is the first release on CNET Download.com.