by Dinesh Thakur

COM1, COM2, and so on are the names of the serial ports in an IBM PC or compatible computer. You can use these names in DOS commands to configure the ports (tell them how fast to transfer data, and what method to use in doing so). In most programs that utilize a serial port, you can pick the port you're working with by name from a menu. You probably have only COM1, or just COMI and COM2.