I downloaded CSerialCom.cpp class from following link – A Simple Class for Implementing Serial Communication in Win-9X/2000 and modified it as follow to handle multiple communication ports. Here is SerialCom.h header file. [crayon-5cb8dd9c365d9731227644/] SerialCom.cpp : implementation file is here [crayon-5cb8dd9c365ee499851819/]