This article mainly introduced the development background and the application demand of the marshalling yard dispatcher production wireless transmission system,and emphatically indicated the system major component to pass on module date RiJing NISSEI ND250A with the RS232 communication agreement and methods, then specify VISUAL BASIC serial communication controller MSCOMM's attributes, method and events.Through the instance to control use the MSCOMM communication to carry on the RS232 serial communication,and the design method to carry on the detailed discussion,and finally realized it under the win2000/xp environment with PC to pass on the module with the RS232 serial communication control.