Motorola MC21XX SERIES, User Manual

Page: 109 / 116

Glossary - 7
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.
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 .
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.
SDK. Software Development Kit
Self-Checking Code. A symbology that uses a checking algorithm to detect encoding errors within the characters of a
bar code symbol.
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.
Soft Reset. See Warm Boot .
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.
Start/Stop Character. A pattern of bars and spaces that provides the scanner with start and stop reading instructions
and scanning direction. The start and stop characters are normally to the left and right margins of a horizontal code.
Subnet. A subset of nodes on a network that are serviced by the same router. See Router .