The paper describes communication mechanism be-tween PC and USB device and the USB device structure designed for multi -floppies working platform developped by author.Fur-thermore,the design idea of impleme nting communication between PC and USB device is also presented.

This paper is about design and realization of communication circuit, which connects three-dimension coordinate input device to computer. Communication protocol and the key technique of device driver are published in this paper. It is told how the applied software is developed on the basis of communication protocol and driver. One applied example is introduced. This paper provides essential technique condition for a broad application of the device.