FUJITSU M3093DG - Manual (Page 134)

f ALD (Automatic Length Detection): Byte 3
The ALD bit specifies detected paper length replaces length value which
has specified in Length field in Set Window Parameter. When this bit is 0,
automatic length detection is disabled. When this bit is 1, automatic
length detection is enabled. After the scanning, detected length
(transferred line number) is set in Detected Paper Length field of Pixel Size
Data.
Example 1:
Length
Width
Image data transfer is
completed at this line.
For the READ command, CHECK CONDITION is returned with ILI=0, if
TLb0 like as image data shrink in compression.
Example 2:
Width ULX
ULY
Length
If Window region is started outside the paper, no image data is returned.
For the READ command, CHECK CONDITION is returned and reading
sequence terminates extraordinarily.
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