dear all. avr(atmega8) reads D30 register Fx-plc Mitsubishi using rs232 to communication. can u support me to explain this instruction Cmd = Chr(02) : Cmd = Cmd + "0103C02" : Cmd = Cmd + Chr(03) : Cmd = Cmd + "6C" its writed by visual basic. I only know char(02): text start, char(03): text end but I don't know "0103C02" and "6C". what is it mean?? pls help me, thanks so much.