Symbol MC909X User Manual page 233

Tolerance. Allowable deviation from the nominal bar or space width.
Transmission Control Protocol/Internet Protocol. See TCP/IP.
TLS. (Transport Layer Security) TLS is a protocol that ensures privacy between communicating applications
and their users on the Internet. When a server and client communicate, TLS ensures that no third party may
eavesdrop or tamper with any message. TLS is the successor to the Secure Sockets Layer (SSL).
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.
U
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.
WAP. (Wireless Application Protocol) A set of specifications, developed by the WAP Forum, that lets developers
using Wireless Markup Language build networked applications designed for handheld wireless devices.
WAP was designed to work within the constraints of these devices: a limited memory and CPU size, small,
monochrome screens, low bandwidth and erratic connections.
WEP. Wired-Equivalent Privacy protocol was specified in the IEEE 802.11 standard to provide a WLAN with a
minimal level of security and privacy comparable to a typical wired LAN, using data encryption.
WPA. Wi-Fi Protected Access is a data encryption specification for 802.11 wireless networks that replaces the
weaker WEP. It improves on WEP by using dynamic keys, Extensible Authentication Protocol to secure
network access, and an encryption method called Temporal Key Integrity Protocol (TKIP) to secure data
transmissions.
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