$COM                     Allocate Serial Port Receive Space

 $COMn size

    Allocates space, in bytes, for the serial port receive buffer.

        size    A numeric expression in the range 0 to 32767.

           n    Must be 1, for COM1:, or 2, for COM2:.

   --------------------------------------------------------------------------

      Notes:    The buffers for COM1: and COM2: can be allocated
                separately in Turbo Basic.

                The default is 256 bytes, although the default value can
                be set and saved in the Options menu.