Glossary - 5

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
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
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.
SDK. Software Development Kit
Shared Key. Shared Key authentication is an algorithm where both the AP and the MU share an authentication key.
SID. System Identification code. An identifier issued by the FCC for each market. It is also broadcast by the cellular
carriers to allow cellular devices to distinguish between the home and roaming service.