DOS Fn 4407H: IOCTL Query Handle Output Status

                                                         Compatibility: 2.0+ 
 Expects: AX    4407H
          BX    file handle  (device or disk file)
 Returns: AX    error code  if CF is set to CY
          AL    output status code (if no error)
                00H: not ready
                ffH: ready
    Info: This function checks to see if a device is ready to receive

          If the handle is a disk file:
            AL always returns with ffH (ready) even if the disk is full or
              no diskette is present etc.

          If the handle is a device:
            AL=00H the device is not ready
            AL=ffH the device is ready (output will be accepted)

   Notes: ■ This fn makes for a simple way to determine if an output
            device, such as a COM port, is ready to accept output.  It is
            not useful for disk files.

See Also: Fn 44H (IOCTL)
          Fn 4406H (Query Handle Input Status)
          DOS Functions