Motorola ET1 User Manual page 119

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.
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 devices.
Tolerance. Allowable deviation from the nominal bar or space width.
Transmission Control Protocol/Internet Protocol. See TCP/IP.
Trivial File Transfer Protocol. See TFTP.
U
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.
V
Visible Laser Diode (VLD). A solid state device which produces visible laser light.
Glossary - 7