该文件实现了串口自发自收，初学者可以从中获取很大益处-realization of the document since the serial spontaneous admission, beginners will be able to reap great benefits

Visual Basic与RS-232串行通讯控制，对于想用VB开发串口通讯的初学者很有帮助。文档格式为PDF，无需解压密码-Visual Basic and RS-232 serial communication control, who want to develop serial communication with VB very helpful for beginners. Document format is PDF, no need to extract the password