Motorola LS3578 - Manual (Page 366)

Glossary - 6 Symbol LS3578 Product Reference Guide
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.
Q
Quiet Zone. A clear space, containing no dark marks, which precedes the start character of a bar code symbol and follows
the stop character.
QWERTY. A standard keyboard commonly used on North American and some European PC keyboards. “QWERTY” refers
to the arrangement of keys on the left side of the third row of keys.
R
Reflectance. Amount of light returned from an illuminated surface.
Resolution. The narrowest element dimension which is distinguished by a particular reading device or printed with a
particular device or method.
RF. Radio Frequency.
RS-232. An Electronic Industries Association (EIA) standard that defines the connector, connector pins, and signals used to
transfer data serially from one device to another.
S
Scan Area. Area intended to contain a symbol.
Scanner. An electronic device used to scan bar code symbols and produce a digitized pattern that corresponds to the bars
and spaces of the symbol. Its three main components are: 1) Light source (laser or photoelectric cell) - illuminates a bar
code,; 2) Photodetector - registers the difference in reflected light (more light reflected from spaces); 3) Signal
conditioning circuit - transforms optical detector output into a digitized bar pattern.
Scanning Mode. The scanner is energized, programmed and ready to read a bar code.
Scanning Sequence. A method of programming or configuring parameters for a bar code reading system by scanning bar
code menus.
Self-Checking Code. A symbology that uses a checking algorithm to detect encoding errors within the characters of a bar
code symbol.
Space. The lighter element of a bar code formed by the background between bars.
Specular Reflection. The mirror-like direct reflection of light from a surface, which can cause difficulty decoding a bar code.