Modbus announced that the Standardization Administration of China (SAC) has formally launched the following three Modbus protocol standards for industrial automation in the People's Republic of China:

• GB/Z 19582.1-2004 Modbus Industrial Automation Network Specification Part 1 Modbus Application Protocol
• GB/Z 19582.2-2004 Modbus Industrial Automation Network Specification Part 2 Modbus Protocol Implementation Guide over Serial Link
• GB/Z 19582.3-2004 Modbus Industrial Automation Network Specification Part 3 Modbus Protocol Implementation Guide over TCP/IP

Ouyang Jinsong, director of standardization, Department of Instrumentation Technology & Economy Institute, People's Republic of China and General Secretary of the National Standardization Technical Committee on Industrial Process Measurement and Control confirmed the standards were effective October 26, 2004.