This statement is used to initialize the serial port. Number1 is used to specify the baud rate. Number2 specifies parity. Number3 specifies stop bits. Number4 specifies bytesize, and Number5 identifies which port to open (see the tables below). OPENCOM does not check the validity of the values you give it.

               (number1)                (number2)
               BAUD RATE                PARITY
          ------+-----------       ------+------------
          VALUE | DESCRIPTION      VALUE | DESCRIPTION
            0   | 110  baud          0   | No Parity
            1   | 150  baud          1   | Odd Parity
            2   | 300  baud          3   | Even Parity
            3   | 600  baud
            4   | 1200 baud            (number3)
            5   | 2400 baud            STOP BITS
            6   | 4800 baud        ------+------------
            7   | 9600 baud        VALUE | DESCRIPTION
                                     0   | One Stop Bit
                                     1   | Two Stop Bits

               (number4)                (number5)
               BYTE SIZE                COM PORT
          ------+------------      ------+------------
          VALUE | DESCRIPTION      VALUE | DESCRIPTION
            2   | 7 Bits             0   | Com1
            3   | 8 Bits             1   | Com2

This statement would open COM1 at 300 baud, No parity, 1 Stop bit, 8 bit bytesize.