Glossary - 9
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 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.
Terminate and Stay Resident (TSR). A program under DOS that ends its foreground execution to remain resident in
memory to service hardware/software interrupts, providing background operation. It remains in memory and may
provide services on behalf of other DOS programs.
TFTP. (Trivial File Transfer Protocol) A version of the TCP/IP FTP (File Transfer Protocol) protocol that has no directory or
password capability. It is the protocol used for upgrading firmware, downloading software and remote booting of diskless
Tolerance. Allowable deviation from the nominal bar or space width.
Transmission Control Protocol/Internet Protocol. See TCP/IP.
Trivial File Transfer Protocol. See TFTP.
TSR. See Terminate and Stay Resident.