Glossary - 11
SMDK. Symbol Mobility Developer’s Kit.
Soft Reset. See Warm Boot.
Space. The lighter element of a bar code formed by the background between bars.
Spectrum24. Symbol’s frequency-hopping, spread spectrum cellular network.
Specular Reflection. The mirror-like direct reflection of light from a surface, which can cause difficulty decoding
a bar code.
Spread Spectrum. A technique for uniformly distributing the information content of a radio signal over a
frequency range larger than normally required for robust transmission of data. Spreading the signal without
adding additional information adds significant redundancy, which allows the data to be recovered in the
presence of strong interfering signals such as noise and jamming signals. The primary advantage of spread
spectrum technology is its ability to provide robust communications in the presence of interfering signals.
Spring Radio Protocol. A radio protocol that may be used by the Symbol Spectrum24 radio card. Symbol
Radio cards that use the Spring protocol also have an Net ID.
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.
STEP. Symbol Terminal Enabler Program.
Subnet. A subset of nodes on a network that are serviced by the same router. See Router.
Subnet Mask. A 32-bit number used to separate the network and host sections of an IP address. A custom
subnet mask subdivides an IP network into smaller subsections. The mask is a binary pattern that is
matched up with the IP address to turn part of the host ID address field into a field for subnets. Default is
often 255.255.255.0.
Substrate. A foundation material on which a substance or image is placed.
Symbol. A scannable unit that encodes data within the conventions of a certain symbology, usually including
start/stop characters, quiet zones, data characters and check characters.
Symbol Aspect Ratio. The ratio of symbol height to symbol width.
Symbol Height. The distance between the outside edges of the quiet zones of the first row and the last row.
Symbol Length. Length of symbol measured from the beginning of the quiet zone (margin) adjacent to the start
character to the end of the quiet zone (margin) adjacent to a stop character.
Symbology. The structural rules and conventions for representing data within a particular bar code type (e.g.
UPC/EAN, Code 39, PDF417, etc.).