Symbol Technologies DS 3408 - Manual (Page 381)

GL-5
EAN/U.P.C. A fixed-length, numeric 13-digit bar code symbol consisting of 30 dark
elements and 29 intervening light elements. Each character is represented by
2 bars and 2 spaces over 7 modules. A bar may be comprised of 1, 2, 3 or 4
modules. Each EAN/U.P.C. symbol consists of a leading quiet zone, a start
pattern, 7 left-hand data characters, a center bar pattern, 5 right-hand data
characters, a Modulo 10 check character, a stop pattern and a trailing quiet
zone. U.P.C. is often considered a 12-digit code. The 13th digit of EAN/U.P.C.
symbol is a derived character in the left-most position. In the case of U.P.C., this
derived left-most character is a 0.
Element Generic term for a bar or space.
Encoded Area Total linear dimension occupied by all characters of a code pattern, including
start/stop characters and data.
Error Correction A reader or decoder's use of mathematical schemes to reconstruct or replace
damaged or missing symbol characters to enable the reading of the symbol
data.
Error Detection This occurs when error-correction characters detect that the presence of errors
in the symbol exceeds the error correction capacity, and keeps the symbol from
being decoded as erroneous data.
Error-Correction Characters Symbol characters used for error correction and detection, calculated
automatically from the other symbol characters.
Error-Correction Level An indicator of the number of characters used in a symbology for error
correction. A higher level of error correction allows for correcting greater
potential symbol damage.
Error-Detection Characters Symbol characters reserved for error detection that are calculated
automatically from the other symbol characters.
Fixed Beam Bar Code Reader A scanning device where scanning motion is achieved by moving the object
relative to the reader; as opposed to a moving beam reader.
Guard Bars Bars located at both ends and the center of a UPC and EAN symbol to provide
reference points for scanning.
Horizontal Bar Code A bar code or symbol with an overall length dimension that is parallel to the
horizon, which resembles a picket fence.
Host Computer A computer that serves other terminals in a network, providing such services
as computation, database access, supervisory programs, and network control.
IEC International Electrotechnical Commission. This international agency regulates
laser safety by specifying various laser operation classes based on power
output during operation.
IEC (825) Class 1 This is the lowest power IEC laser classification. Conformity is ensured through
a software restriction of 120 seconds of laser operation within any 1000 second
window and an automatic laser shutdown if the scanner's oscillating mirror
fails.
Intercharacter Gap The space between two adjacent bar code characters in a discrete code.
Interleaved 2 of 5 A binary bar code symbology representing character pairs in groups of five bars
and five interleaved spaces. Interleaving provides for greater information
density. The location of wide elements (bar/spaces) within each group
determines which characters are encoded. This continuous code type uses no
intercharacter spaces. Only numeric (0 to 9) and START/STOP characters may
be encoded.
Interleaved Bar Code A bar code in which characters are paired together, using bars to represent the
first character and the intervening spaces to represent the second.