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.
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.
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.).
TCP/IP. (Transmission Control Protocol/Internet Protocol) A communications protocol used to internetwork dissimilar
systems. This standard is the protocol of the Internet and has become the global standard for communications. TCP
provides transport functions, which ensures that the total amount of bytes sent is received correctly at the other end.
UDP is an alternate transport that does not guarantee delivery. It is widely used for real-time voice and video
transmissions where erroneous packets are not retransmitted. IP provides the routing mechanism. TCP/IP is a routable
protocol, which means that all messages contain not only the address of the destination station, but the address of a
destination network. This allows TCP/IP messages to be sent to multiple networks within an organization or around the
world, hence its use in the worldwide Internet. Every client and server in a TCP/IP network requires an IP address, which
is either permanently assigned or dynamically assigned at startup.
Telnet. A terminal emulation protocol commonly used on the Internet and TCP/IP-based networks. It allows a user at a
terminal or computer to log onto a remote device and run a program.
Terminal. See Mobile Computer.
Terminal Emulation. A "terminal emulation" emulates a character-based mainframe session on a remote non-mainframe
terminal, including all display features, commands and function keys. The VC5000 Series supports Terminal Emulations
in 3270, 5250 and VT220.
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