Rockwell Automation 2755-G6-D Scanner with RS-232 Option - Manual (Page 99)

Glossary
G–4
self-checking: A bar code or symbol using a checking
algorithm which can be applied to each character to guard
against undetected errors. Codes that are not
self-checking may employ a check digit or other
redundancy in addition to the data message.
space: The lighter element of a bar code formed by the
background between bars.
start/stop characters: Bar code characters that provide
the scanner with information on how the code is bounded
and its orientation. The start character is normally at the
left end of a horizontal code and adjacent to the most
significant character. The stop character is normally at the
end of a horizontal code and adjacent to the least
significant character.
symbology: The conventions, or rules, which govern the
formation of characters and strings in bar codes. The
language of the bar code symbol.
symbol density: The number of characters per
linear inch.
symbol length: The length of the symbol measured from
the beginning of the quiet area adjacent to the start
character to the end of the quiet area adjacent to a stop
character.
UPC: Acronym for Universal Product Code. The
standard bar code for retail food packages in the
United States.
vertical bar code: A code pattern in which the overall
coded area from start to stop is perpendicular to the
horizon. The individual bars appear as rungs of a ladder.