GLOSSARY OF RFID TERMS: T - Z
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T
Tag: See RFID tag
Tag excitation device: A term coined by the RFID Alliance Lab to refer to a device that sends signals to the tag regardless of the make or manufacturer. TED is used to measure the response of tags scientficially.
Tag talks first: A means by which a reader in a passive UHF system identifies tags in the field. When tags enter the reader's field, they immediately communicate their presence by reflecting back a signal. This is useful when you want to know everything that is passing a reader, such as when items are moving quickly on a conveyor. In other cases, the reader wants to simply find specific tags in a field, in which case it wants to broadcast a signal and have only certain tags respond. (See Reader talks first.)
Tamper-evident tag: An RFID tag that communicates to a reader when a package or container has been opened without authorization.
TDMA: See time division multiple access
TED: See tag excitation device
Time division multiple access: A method of solving the problem of the signals of two readers colliding. Algorithms are used to make sure the readers attempt to read tags at different times.
Transponder: A radio transmitter-receiver that is activated when it receives a predetermined signal. RFID transponders come in many forms, including smart labels, simple tags, smart cards and keychain fobs. RFID tags are sometimes referred to as transponders.
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U
UCC: See Uniform Code Council
UHF: See ultra-high frequency
UID: See Unique Identification
Ultra-high frequency: From 300 MHz to 3 GHz. Typically, RFID tags that operate between 866 MHz to 960 MHz. They can send information faster and farther than high- and low-frequency tags. But radio waves don’t pass through items with high water content, such as fruit, at these frequencies.
Ultra-Wideband: Any radio technology having a bandwidth exceeding the lesser of 500 MHz or 20 percent of the arithmetic center frequency, according to the Federal Communications Commission (FCC). Due to the extremely low emission levels currently allowed by regulatory agencies, UWB systems tend to be short-range and used indoors. High data-rate UWB can enable wireless monitors, the wireless printing of digital pictures from a camera without an intervening personal computer and the transfer of files among cell phone handsets and other handheld devices, such as personal digital audio and video players. UWB is used in location systems and real-time location systems.
Uniform Code Council: The nonprofit organization that oversees the Universal Product Code, the bar code standard used in North America.
Unique Identification: A numbering scheme used by the U.S. Department of Defense to track high-value items and items, such as chemical suits, that have an expiration date.
Unique identifier: A unique serial number that identifies the transponder.
Universal Product Code: A generic term that refers to the 12 digit data structure encoded in a UCC bar codes.
Universal Serial Bus: An external peripheral interface standard for communication between a computer and external peripherals over an inexpensive cable. Many newer RFID readers can connect to computers via a USB port.
UPC: See Universal Product Code
USB: See Universal Serial Bus
UWB: Any radio technology having a bandwidth exceeding the lesser of 500 MHz or 20 percent of the arithmetic center frequency, according to the Federal Communications Commission (FCC). Due to the extremely low emission levels currently allowed by regulatory agencies, UWB systems tend to be short-range and used indoors. High data-rate UWB can enable wireless monitors, the wireless printing of digital pictures from a camera without an intervening personal computer and the transfer of files among cell phone handsets and other handheld devices, such as personal digital audio and video players. UWB is used in location systems and real-time location systems.
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V
Voltage standing wave ratio: A standing wave may be formed when a wave is transmitted into one end of a transmission line and is reflected from the other end by an impedance mismatch. The Voltage standing wave ratio is the ratio of maximum to minimum voltage in a standing wave pattern. It may be stated as a ratio (VSWR) or in dB (return loss).
VSWR: See voltage standing wave ratio
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W
Warehouse Management System: A key component of the supply chain, intended to control the movement and storage of materials within a warehouse and process the associated transactions, including shipping, receiving, putaway and picking. Such systems also direct and optimize stock putaway based on real-time information about the status of bin utilization. WMSs utilize auto-ID data-capture technology, such as bar-code scanners, mobile computers, wireless LANs and RFID, to efficiently monitor the flow of products.
Wi-Fi: The generic wireless interface of mobile computing devices, such as laptops used in local area networks (LANs). The term "Wi-Fi" (a play on the term "Hi-Fi") is thought to be an abbreviation for "wireless fidelity." Common uses include Internet and voice-over-IP phone access, gaming and network connectivity for such consumer electronics as televisions, DVD players and digital cameras. In spite of media reports about possible health risks from Wi-Fi, scientific studies have failed to show a causal effect.
WIP Tracking: See Work-in-process tracking.
Wireless Markup Language: WML is a markup language that is based on XML (eXtensible Markup Language). The official WML specification is developed and maintained by the WAP Forum, an industry-wide consortium founded by Nokia, Phone.com, Motorola, and Ericsson. This specification defines the syntax, variables, and elements used in a valid WML file.
WML: See Wireless Markup Language
Work-in-process Tracking: Manufacturers often have to add parts to subassemblies or perform a series of processes on goods being manufactured. Using RFID to track work-in-process reduces manual data collection and can help ensure that the right processes are preformed at the proper time on the correct product.
WORM: See write once, read many
Write once, read many: A tag that can be written to only once by the user. Thereafter, the tag can only be read.
Write range: The distance from which data can be written to an RFID tag.
Write rate: The rate at which information is transferred to a tag, written into the tag's memory and verified as being correct.
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X
X12 EDI: An electronic data interchange schema developed for the American National Standards Institute for inter-industry electronic exchange of business transactions data.
XML: See eXtensible Markup Language
XML Query Language: A method of searching a database based on the extensible markup language (XML). Files created using the Auto-ID Center’s Physical Markup Language can be searched using XQL.
XQL: See XML Query Language
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Z
ZigBee: A specification for a suite of high-level communication protocols using small, low-power digital radios based on the IEEE 802.15.4 standard for wireless personal area networks (WPANs). ZigBee is targeted at RF applications requiring a low data rate, long battery life and secure networking.
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