AMT Datasouth PAL - Manual (Page 57)

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_barcode: PDF-417
/Truncate
/TR Boolean. true instructs PAL to not draw the right side indicators
and right stop pattern for the bar code. false instructs PAL to
draw these patterns. Default = false.
Usage Notes
Error correction coding (ECC) consists of additional data added to the user’s data in order to
facilitate recovery of the user’s data even when the bar code has been damaged and cannot be fully
scanned. PDF-417 provides two different mechanisms for specifying the amount of ECC to include
within the bar code.
EccPercent allows the user to specify the amount of error correction codes to add to the data as a
percentage of the data. The larger the EccPercent value, the more damage the bar code can
sustain while still allowing the scanner to recover 100% of the user’s data.
EccLevel allows the user to select the amount of error correction codes added to the data based on
predetermined values established for PDF-417 bar codes. EccLevel setting manages error
correction and detection during scanning based on the following equation.
faults = errors + 2 × misdecodes
where
errors = the number of unscannable codewords.
misdecodes = number of misdecoded codewords.
The following table gives the number of faults per EccLevel setting which the scanning process
can tolerate and still be able to recover 100% of the user’s data.
EccLevel faults
0 0
1 2
2 6
3 14
4 30
5 62
6 126
7 254
8 510
Due to the advanced nature of the two dimensional PDF-417 symbology, the control parameters
associated with thesymbology have a much higher level of complexity.than more traditional one
dimensional bar codes. Most of the configuration parameters provided by PAL exist to allow the
user extra control over the creation of the bar code.
The user will find that allowing the printer to produce PDF-417 bar codes using the printer’s built-
in default parameters will prove as simple as printing single dimension bar codes. Therefore, users
not familiar with details of PDF-417 bar codes should start by using the printer’s built-in defaults.
Then, if necessary, the user should add only one or two PDF-417 configuration parameters at a
time in order to observe the affect of the parameters upon the bar code.