Glossary - 10
LI4278 PRODUCT REFERENCE GUIDE
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
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.
UDP. User Datagram Protocol. A protocol within the IP protocol suite that is used in place of TCP when a reliable
delivery is not required. For example, UDP is used for real-time audio and video traffic where lost packets are simply
ignored, because there is no time to retransmit. If UDP is used and a reliable delivery is required, packet sequence
checking and error notification must be written into the applications.
UPC. Universal Product Code. A relatively complex numeric symbology. Each character consists of two bars and two
spaces, each of which is any of four widths. The standard symbology for retail food packages in the United States.
Visible Laser Diode (VLD). A solid state device which produces visible laser light.
Warm Boot. A warm boot restarts the mobile computer by closing all running programs. All data that is not saved to
flash memory is lost.