When attendance not communication , What will be the reason? 

RE:Possible reasons

□ Incorrectness communication port setting, linking the communication port is not used in the actual COM ports;

□ Difference of Computer communications port and attendance for the Baud Rate setting value;

□ Attendance not connected to the power or not connected to computer;

□ Attendance connected but not boot-strap;

□ Incorrect terminals connecting;

□ Data line or converters not communications;

□ Cyber-COM port ruin.