Wincor Nixdorf TH250, Programmer'S Manual

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TH250 Programmer’s Guide
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rows are selectable, which allows the aspect ratio to be adjusted to particular labeling applications.
There are no separator bars between rows.
Each character has four bars and four spaces within 17 modules, and is assigned a value between 0
and 928. For this symbology, it is common to refer to these character values as “code words.”
There are three mutually exclusive sets of symbol patterns, or clusters, each having 929 distinct
patterns. Because different clusters are used for adjacent rows, it is possible for the decoder to tell
if the scanning path is crossing row boundaries without the use of separator bars.
Sample symbol description:
Each PDF 417 symbol consists of 3 to 90 stacked rows surrounded on all four sides by a quiet zone.
Each row contains:
1
Leading quiet zone
2 Start pattern
3 Left row indicator characters (code words)
4 One to thirty data characters (code words)
5 Right row indicator character (code words)
6 Stop pattern
7 Trailing quiet zone
The number of characters in a row and number of rows can be adjusted to vary the symbol’s
overall aspect ratio to best fit an available space.
Each row has a left and right row indicator with a data region between. The left-most character in
the top row of the data region is the total number of characters in the data region, excluding error
correction characters. Characters within the data region are designed to be read from left to right,
starting on the top row, immediately after the length-defining character.
The maximum characters in the data region are 928.
Related Information:
The “Set bar code width” command (1D 77 n) affects the x dimension and row height for PDF 417.
See chart below.
n value
x dimension row height
2 2 7
3 3 10
4 4 13
5 5 17
6 6 20