Motorola MC9500-K User Manual page 272

Glossary - 8 MC9500-K Mobile Computer User 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
RAM. Random Access Memory. Data in RAM can be accessed in random order, and quickly written and read.
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.
ROM. Read-Only Memory. Data stored in ROM cannot be changed or removed.
Router. A device that connects networks and supports the required protocols for packet filtering. Routers are typically used
to extend the range of cabling and to organize the topology of a network into subnets. See Subnet.
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.