User's Manual

Psion Teklogix 7545 Hand-Held Computer User Manual C-45
Appendix C: Bar Code Settings
Imager
Code 39
Adaptive Windowing
“Adaptive Windowing” is an advanced technique used to speed up bar code recognition in
certain applications. This parameter automatically reduces the size of the window to the
user-programmed window size when it successfully decodes (which reduces decode time
the next time it is used), but increases it to the full size window on a failed decode.
Constant Illumination
“Constant Illumination” is used to reduce the intrusiveness of the device’s illumination on
the observer. Instead of the illumination turning on and off every time the device attempts a
decode (2-4 times per second), the illumination stays on from the time the trigger is pulled
until a decode is successful. This feature is useful in low light environments, since it will
also reduce the distraction that the illumination can have on nearby co-workers.
C.4.3 Code 39
Enabled
Set this parameter to on to enable “Code 39”.
Full ASCII
If this parameter is enabled, the characters +, %, and / are used as escape characters. The
combination of an escape character and the next character is converted to an equivalent
ASCII character.
Check Digit Verification
When this parameter is enabled, the integrity of a “Code 39” symbol is checked to ensure
that it complies with specified algorithms.
Note: When decoding multiple bar codes in one image, the value assigned to ‘Decoder
Timeout’ should be increased to 200ms/extra bar code after the first.
Note: This feature assumes that you have reached an understanding about how the device
operates in your application, and that, after a learning period, operators will get
used to using the imager in one particular way. It also assumes that a trained oper-
ator will usually only have near miss scenarios.
Note: Only those “Code 39” symbols that include a MOD 43 check digit are decoded
when this parameter is enabled.
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