Glossary Of Rfid Terms -- 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.

Track and trace

The process of retrieving information about the movement and location of goods.

Transceiver

A device that both transmits and receives radio waves.

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.

Type A Reference Interval (TARI)

The duration of a pulse of energy sent to UHF EPC Gen 2 tags to indicate a 0 in binary code. EPC Gen 2-compliant readers use pulse interval encoding (PIE) to code binary data. A binary '0' is indicated by a short, high-level pulse, followed by a low pulse of equal length. The length of a TARI can vary from 6.25 to 25 microseconds.