Motorola DS4208, Product Reference Manual

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User Preferences & Miscellaneous Digital Scanner Options 4 - 27
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When defining regions:
• Defining a region much larger than the bar code improves tolerance to scan distance and angle, but can
cause a decode of a nearby bar code instead of the target bar code. Therefore, for best performance
define larger regions when only a few bar codes are in view and those in view are widely separated.
• Defining a region close to (or smaller than) the target bar code improves the probability of decoding this
bar code rather than one nearby, but scan distance and angle must be more accurate. Therefore, for best
performance define small regions when many bar codes are in view or those in view are close together.
•
Use Region elements to improve decode speeds by reducing the image area to search for the target bar
code.
•
Specifying Code Type may also improve decode speeds for some code types.
•
Although you can scan parameter bar codes when multicode mode is enabled, be aware of the following: If
the multicode expression defined a region(s), to scan a parameter bar code you must position the bar code
within the first region defined in the expression. In some cases, this first region is not the center of the image
and aiming at the parameter bar code does not result in a successful decode.
The following examples show the multicode expressions in both hex and decimal formats, however in the sample
figures the values are decimal. Be sure to use the correct base numbering system when creating an expression. A
region specified as 0x00 0x00 0x64 0x32 represents a region with coordinates of Top-Left (0,0) and Bottom Right
(100,50).
Example 1
To decode one Code 128 bar code anywhere in the image (even when bar codes of other types are in view), as in
Figure 4-1 , program the expression as follows:
The expression in decimal is (formatted for readability):
1 C 2 0 8 ;
To program the expression via scanning parameters the sequence is (spaces are for readability):
[MultiCode-Expression] 01 C 02 00 08 ; [End Of Message]