说明：  USB技术的先进性使得设计者在PC外设开发中首选USB接口，而在现有虚拟仪器开发平台如LabWindows／CVI中并没有提供直接支持USB接口的函数库，基于这种情况，笔者利用FTDI公司的FT232AM完成RS232和USB之间的接口转换，然后再对USB接口实现间接的数据读写。
(USB technology allows the designers of the advanced nature of PC peripherals in the development of the preferred USB interface, and virtual instruments in the existing development platforms such as LabWindows/CVI does not provide direct support for USB interface library, based on this situation, I use FTDI FT232AM completion of the company s RS232 and USB interface between the conversion and then to the USB interface to read and write data indirectly.)