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)
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DOS Fn 4407H: IOCTL Query Handle Output Status