Abstract: The system is presented in which the plugged program technology is adopted, and in which the Control Area-Networks Bus is used as a communicating flat. In order to Integrated Controlling all different NC system, the communication protocol's core has to resolve the problem of communicating competition in real-time, avoid the influence of dirt and vary temperature, transmit the NC programs simultaneously to all NC systems, request NC program from the machine tool's operation panel, realize that the date of PDM/CAD/CAPP/CAM and DNC is shared. This system is able to be applied in every NC manufacturing workshop.

Key words: DNC, Field-bus, Integrated manufacturing, Numerical control