串口通信教程，有点意思，通俗易懂，特别好使！ 真的-Serial communication tutorial, a bit mean, easy to understand, especially so! True

采集25扇门的开关状态,在面板上用红LED指示开,绿LED指示关,并把25扇门的开关状态用NMEA语句从RS422发送给上位机.-detect the 25pcs watertight door open/close status, and display the status of each door in panel, red LED mean open, green LED means close, meanwhile these information will be send out