几个USB转串口RS—232c的原理图，配转换芯片的datasheet。-Some USB to Serial RS-232c of the schematic diagram, with the conversion chip datasheet.

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