RS232 串口介绍和初步了解，包含DB9引脚定义，电气特性说明，电路图说明，参数说明，

具体传输格式，传输的波形， 对设计Rs232的应用者很有帮助，简单明了易懂。

-Introduction and preliminary understanding of the RS232 serial port, including the DB9 pin definitions, electrical characteristics, circuit descr iption, parameter descr iptions, specific transmission format, transmission of the waveform, the application of the design were very helpful Rs232, simple to understand.