Remain part of reading data from multiple serial ports is as follows. Handler.h file #include "SerialCom.h" class Handler { private: CSerialCom port; BYTE data; DWORD BaudRate; BYTE byteSize; DWORD fparity; BYTE parity; BYTE stopBit; public: Handler(void); void setPortDetail(DWORD BaudRate,BYTE byteSize,DWORD fparity,BYTE parity, BYTE stopBit); void COMListen(); void listenCOM(); ~Handler(void); }; Handler.cpp class #include "Handler.h" #include