Motorola Symbol MS4404 Integration Manual page 416

Glossary - 8 Symbol MS4404/MS4407 Integration Guide
Non-read. The absence of data at the scanner output after an attempted scan, which is due to no code, defective code,
scanner failure or operator error.
O
Omnidirectional. Bar codes read in any orientation relative to the scanner.
Optical Throw. The distance from the scanner face to the closest point at which symbol can be read; also, optical throw is
the difference between range and depth of field.
Orientation. The alignment of the symbol's scan path. Two possible orientations are horizontal with vertical bars and spaces
(picket fence) and vertical with horizontal bars and spaces (ladder).
Overhead. The fixed number of characters required for start, stop and checking in a given symbol. For example, a symbol
requiring a start, stop and 2 check characters contains 4 characters of overhead.
P
Parameter. A variable that can have different values assigned to it.
PDF417. An error correcting 2-dimensional multi-row symbol developed in 1992 by Symbol Technologies, PDF417 symbols
are constructed from 4 bars and 4 spaces over 17 modules. The symbol size is from 3 to 90 rows. There is no specified
minimum or maximum for X or Y dimension. With at least the recommended minimum level of error correction, the
recommended Y dimension is 3X. With less than the minimum recommended level of error correction, the recommended
Y dimension is 4X. A quiet zone of 2X is specified on each side of a symbol. Because of delta decode techniques, the
symbology is immune from uniform bar width growth. PDF417 supports cross-row scanning. The intellectual property
rights associated with PDF417 have been committed to the public domain.
Percent Decode. The average probability that a single scan of a bar code would result in a successful decode. In a
well-designed bar code scanning system, that probability should approach near 100%.
Pitch. Rotation of a bar code symbol in an axis parallel to the direction of the bars.
Plessey Code. A pulse-width, modulated bar code commonly used for shelf marking in grocery stores.
Postnet Code. Code developed by the U.S. Postal Service to assist in the automatic sorting of mail.
Print Contrast Signal (PCS). Measurement of the contrast (brightness difference) between the bars and spaces of a
symbol. A minimum PCS value is needed for a bar code symbol to be scannable. PCS = (RL - RD) / RL, where RL is
the reflectance factor of the background and RD the reflectance factor of the dark bars.
Programming Mode. The state in which a scanner is configured for parameter values. See Scanning Mode.