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MDI-4000 Series Serial Interface Manual
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6.2.2 Positive and Negative Image of Barcodes (1D Code Common)
Barcodes are typically printed in black on a white background and are called normal or positive
barcodes. But, sometimes they are printed in white on a black background, which are called
negative barcodes.
Positive Image of Code 128 Negative Image of Code 128
Figure 38: Positive and Negative Barcode Images
1D Positive and Negative Barcode Commands
Command Description Default
[DLA Q0 Decode positive barcodes only.
✓
Q1 Decode negative barcodes only.
Q2 Decode positive barcodes and negative barcodes.
* For best reading performance, only enable the barcodes you need.
6.2.3 Quiet Zone (1D Code Common)
The quiet zone is the blank margin on either side of a barcode that tells the scan engine where
the barcode starts and stops. You can configure the scan engine to decode barcodes that have
smaller start or end margins than specified for the symbology.
Note: Only use smaller margin checks when necessary. This option may increase the possibility
of partial and ghost reads.
Figure 39: Quiet Zone
Margin Check Commands
Command Description Default
YN No margin check
YO Margin check 1/7 nominal
YP Margin check 2/7 nominal
YQ Margin check 3/7 nominal
YR Margin check 4/7 nominal
YS Margin check 5/7 nominal
YT Margin check 6/7 nominal
YU Margin check nominal
✓
Quiet Zone