89C2051在这里的基本作用是检测外接的多路有线报警传感器的报警电平信号，并转化成一一对应的“COMSMSXX”指令，最后从串口以9600BIT/S、8、N、1的格式发送给JB35/JB35G，触发JB35/JB35G“报警设置（2）”中的报警短信。由于89C2051口线的限制，我们只扩展了12路外接传感器并口输入口，如果用户需要把20路都转化成并口输入口，那就要用更多口线的单片机来实现，如89C51等。-89C2051 here the basic role is to detect external road many wired alarm sensor alarm level signal, and one-to-one into the " COMSMSXX"　command, and finally from the serial port to 9600BIT/S, 8, N, 1 format sent to JB35/JB35G, trigger JB35/JB35G " alarm settings (2)"　in the alarm message. 89C2051 mouth lines because of the restrictions, we can only extend the road 12 parallel port external sensor input, if users need to put all 20 into a parallel road input, then I use more lines to achieve single-chip microcomputer, such as 89C51, etc..