Glossary - 11
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.
U
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.
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.
V
Visible Laser Diode (VLD). A solid state device which produces visible laser light.
W
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.