Rockwell Automation 2755 2D Hand-Held Scanner - Manual (Page 127)

Glossary G–13
Publication 2755-6.4
Start / Stop Character
A pattern of bars and spaces that provides the scanner with start and
stop reading instructions and scanning direction. The start and stop
characters are normally to the left and right margins of a horizontal
code.
Symbol
A scannable unit that encodes data within the conventions of a
certain symbology, usually including start/stop characters, quiet
zones, data characters, and check characters.
Symbol Aspect Ratio
The ratio of symbol height to symbol width.
Symbol Height
The distance between the outside edges of the quiet zones of the first
row and the last row.
Symbol Width
Length of symbol measured from the beginning of the quiet zone
(margin) adjacent to the start character to the end of the quiet zone
(margin) adjacent to a stop character.
Symbology
The structural rules and conventions for representing data within a
particular bar code type (e.g. UPC/EAN, Code 39).
Symmetric Bar Width Growth
Uniform growth of bars evenly distributed.
T
Tolerance
Allowable deviation from the nominal bar or space width.
Two-Dimensional Symbology
Designed for high information density and higher encoding
capability than one-dimensional bar codes, a symbology which
encodes data in both the horizontal (X-dimension) and vertical
dimensions, usually in a stacked or multi-row arrangement.