Design And Implementation Of The Usb-rs232 Interface Converter

With the development of computer technology, especially technology of computer hardware, the traditional RS232 serial port has proved to come with more and more disadvantages, while various devices such as measuring appliances and instruments, industrial controlling systems, long-range data terminals are now dependent on the application of RS232 serial interface or its variety as the main ways of telecommunications, which are incompatible with the current leading connection of the external instrumentation. And PC mainly apply USB bus with new-model connection with such characters as plug and play, when designed, some main engines can only sustain USB bus.The following article delivers a design proposal from USB connection switch to RS232 seamless transformation switch, which enables traditional equipment to use former RS232 connection switch to realize the bidirectional data transmission with the USB bus connection switch. And this proposal has such functions of bidirectional cushions as plug and play, easy to operate, high ratio of performance-to-price.The article mainly discusses the current situation of peripheral device connection of PC machine: relative laws of USB connection; design details of realizing the transmission from USB to RS232 connection switch; design details of firmware; design details of USB device driver and application; verifies and applies of switch system.The test of this design proposal has served the anticipated purpose. The experiences and files in this design of transmission from USB to RS232 switch can be very valuable references for other developments on the basis of the intelligent measuring appliances and controlling devices of USB connection.