Glossary of Commonly Used Terms

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z

A

Active Tag - An RFID tag that uses an internal battery to power its microchip and communicate with a reader. Active tags are usually larger than, can transmit over the greatest distances (100+ feet) and can have larger memories than passive tags. The smallest active tags are about the size of a coin and sell for a few dollars. Since they are typically more expensive than passive tags, they are used to track high value goods like vehicles and large containers of merchandise. One common use is to mount one in a vehicle to allow for automated toll collection. TOP OF PAGE

Agile Reader - A reader that can read different types of RFID tags - either operating on different frequencies or different standards - class 1 & class 0 - in the same frequency. TOP OF PAGE

Air Interface - refers to the portion of the system that uses radio waves or RF to invisibly transfer information from the tag to the reader and vice versa. TOP OF PAGE

Antenna - A device that converts radio frequency electric current to electromagnetic waves that are then radiated into the surrounding area. Every wireless system has an antenna. Without it the RFID system will not work. Since the antenna is common to both transmit and receive, it could have the biggest impact on the systems performance. TOP OF PAGE

Antenna Size - Generally speaking, the larger the antenna on the tag, the longer the read range. Since the antenna is basically a circuit that is the means by which power is supplied to the tag to allow the tag to modulate the carrier signal to communicate back to the reader, the smaller the tag, the less energy is induced in the circuit and the weaker the signal response. TOP OF PAGE

Anti-Collision - A feature of RFID systems that enables a batch of tags to be read in one reader field by preventing the radio waves from interfering with one another. It also prevents individual tags from being read more than once. TOP OF PAGE

Automatic Data Capture (ADC) - Methods of collecting data and entering it directly into a computer system without human intervention. Automatic Identifications (Auto-ID) refers to any technology for capturing and processing data into a computer system without using a keyboard. Includes bar coding, RFID and voice recognition. TOP OF PAGE

B

Bit - The smallest unit of digital information - A binary code - a single '0' or '1', where many different codes can be developed to represent pertinent information. A 96-bit EPC is a string of 96 zeros and ones. TOP OF PAGE

Byte - 1 byte = 8 bits. One byte of memory is needed to generate an alpha character or digit. So bytes can be thought of in terms of characters. TOP OF PAGE

C

Challenge-Response Protocols - In these protocols, secret tag information is never sent over the insecure channel between tag and reader. Rather, the reader issues a challenge to the tag, which responds with a result computed using a cryptographic circuit keyed with some secret value. Such protocols may be based on symmetric or public key cryptography. TOP OF PAGE

Chip Based RFID - Refers to RFID tags that contain a integrated circuit and therefore can store a unique serial number or other information and transmit that information to a reader. TOP OF PAGE

Collision - See Tag Collision

Cryptographically-Enabled Tags - Active tags that use cryptography to prevent tag cloning. Some tags have the tag identifier information change after each scan, which reduces the usefulness of observed responses. More sophisticated (dramatically higher cost) devices engage in challenge-response protocols where the tag interacts with the reader to confirm who the reader is. An example of the latter technique is the Exxon-Mobil "Speedpass" used for making automatic payments for gasoline. TOP OF PAGE

D

De-tune - UHF antennas are tuned to receive RFID waves of a certain length from a reader, just as the tuner on a car radio changes the antenna to tune in (receive) signals of different frequencies. When a UHF antenna is close to metal or metallic material, the antenna can be detuned, resulting in poor performance. TOP OF PAGE

E

Electronic Article Surveillance Tags (EAS) - Single bit (either 'on' or 'off') electronic tags used to detect items for anti-theft purposes. EAS technology is similar to RFID in that it uses similar frequency bands. Also many of the 13.56 MHz RFID chips contain a built-in EAS function. TOP OF PAGE

Electronic Product Code (EPC) - Is the next generation of product identification. The EPC is a simple compact, 64 bit or 96 bit "license plate" that uniquely identifies objects (items, cases, pallets, locations, etc.) in the supply chain. The EPC is built around a basic hierarchical idea that can be used to express a wide variety of different, existing numbering systems, like the EAN.UCC system keys, UID, VIN, and other numbering systems. Like many current numbering schemes used in commerce, the EPC is divided into numbers that identify the manufacturer and product type. The EPC, however, uses an extra set of digits, a serial number, to identify unique items. TOP OF PAGE

Electromagnetic Compatibility (EMC) - The ability of a technology or product to coexist in an environment with other electro-magnetic devices. TOP OF PAGE

EPCglobal, Inc. - EPCglobal is a joint venture between EAN International and the Uniform Code Council, Inc, which is responsible for Universal Product Codes (UPC barcodes). It is a not-for-profit organization entrusted by industry to establish and support the Electronic Product Code (EPC) Network as the global standard for immediate, automatic, and accurate identification of any item in the supply chain of any company, in any industry, anywhere in the world. EPCglobal's objective is to drive global adoption of this next generation of product identification schemes. EPCglobal develops standards to support the use of RFID in today's fast moving, information rich trading networks. TOP OF PAGE

F

Frequency - Refers to a band of operation for radio-based technologies. Frequencies allocated for RFID use exist in the low (125Khz), high (13.56 MHz), ultra-high (860 to 960 MHz) and microwave (2.45 Ghz) frequency bands. Each frequency has its own advantages and disadvantages such as read distance, tag size and resistance to electronic noise. TOP OF PAGE

Frequency Regulation - There is no global public body that governs the frequencies used for RFID. In principle, every country can set its own rules for this. Some of the main bodies for governing frequency allocation for RFID are:

• USA: FCC (Federal Communications Commission)
• Canada: DOC (Department of Communications)
• Europe: ERO, CEPT & ETSI
• China: Ministry of Information Industry
• Australia: Australian Communications & Media Authority

G

GTAG (Global Tag) - A standardization initiative of Uniform Code Council (UCC) and the European Article Numbering Association (EAN) for supply chain tracking applications using UHF RFID frequencies. TOP OF PAGE

H

High-Frequency RFID (13.56 MHz) - RFID that uses 13.56 MHz radio frequency band. Features medium sized tags and relatively good reading distances. In the U.S. 13.56 MHz tags can be typically read at approximately 3 - 4 inches with a handheld reader and up to 3 feet with a portal reader. Both read-only and read/write chips are available in this frequency. Two ISO Standards define RFID performance in this frequency, ISO 14443 for proximity applications such as contactless smart cards and ISO 15693 for proximity applications such as item and asset tracking. TOP OF PAGE

I

Integrated Circuit (IC) - Another name for a microchip TOP OF PAGE

Interrogator - See Reader

ISO - (International Organization for Standardization) - An international standard-setting body composed of representatives from national standards bodies. Founded in 1947, the organization produces worldwide industrial and commercial standards, the so-called ISO standards. TOP OF PAGE

L

Line-of-Sight - Technology that requires an item to be "seen" to be automatically identified by a machine. Unlike bar codes and OCR technologies, RFID tags can be read "through" merchandise and most packaging with no line of sight required. TOP OF PAGE

Low-Cost RFID - Typically refers to RFID tags that cost less than $1.00 with typically 3 feet of read range. TOP OF PAGE

Low Frequency RFID (125 & 134 KHz) - Low frequency radio band allocated for RFID use. The main disadvantage of low frequency RFID is its cost and relatively slow data transfer as well as it inability to read many tags at the same time. TOP OF PAGE

M

Multiple Tag Read/Write - Refers to the ability of RFID systems to read multiple tags at the same time. Reading and writing of multiple tags is achieved through the anti-collision feature programmed into the chip. TOP OF PAGE

Microwave RFID Frequency (2,450 MHz or 2.45 GHz) - A microwave frequency band allocated for RFID use. Typically microwave RFID technologies feature the smallest label footprint and long read distances. Typical applications include industrial asset tracking with long range reads and automated toll collection - toll lanes, and rail car tracking. TOP OF PAGE

N

Near-field Communication - RFID antennas emit electromagnetic radiation (radio waves). If an RFID tag is within full wavelength of the reader, it is sometimes said to be in the "near field". If it is more than the distance of one full wavelength away, it is said to be in the 'far field." Passive RFID systems that rely on near-field communication (typically low- and high-frequency systems) have a shorter read range than those that use far field communication (UHF & Microwave systems). TOP OF PAGE

Non-volatile Memory - A generic term for the memory that holds its contents after power has been removed. EPROM, EEPROM and FLASH are examples of non-volatile memory. TOP OF PAGE

Null Spot - Area in the reader field that doesn't receive radio waves. This is essentially the reader's blind spot. It is a phenomenon common to UHF systems. TOP OF PAGE

O

Orientation - The position of a tag antenna vis-à-vis a reader antenna. With UHF systems, readers can be either circular-polarized or linear-polarized. When using a linear polarized antenna, the tag reader and antenna reader must be in alignment in order to achieve the longest reading distance. If that tag antenna is aligned vertically and the reader is sending out signals horizontally, only a small portion of the energy emitted by the reader will hit the tag antenna. TOP OF PAGE

P

Passive RFID Tag - An RFID tag that does not use a battery. Passive tags draw their power from the reader field. The reader transmits a low power radio signal through its antenna. The tag in turn receives it through its own antenna to power the integrated circuit (chip). Using the energy it gets from the signal, the tag will briefly converse with the reader for verification and the exchange of data. As a result, passive tags can transmit information over shorter distances (typically 10 feet or less) than active tags. They are considerably lower in cost ($0.30 or less) making them ideal for tracking lower cost items. TOP OF PAGE

Perpetual Inventory - The ability to know one's inventory position at any given time. RFID offers the promise of being able to perform automatic inventory counts. TOP OF PAGE

R

Radio Frequency Identifications (RFID) - A method of identifying tagged items using radio waves. Radio waves do not require line of site and can pass through materials like cardboard and plastic but not metals and some liquids. TOP OF PAGE

Read-Only Tags - Tags that contain data that cannot be changed. Read-only chips are less expensive than read-write chips. TOP OF PAGE

Read Range - The distance from which a reader can communicate with a tag. Several factors including frequency used, orientation of the tag, power of the reader and design of the antenna affect read range. TOP OF PAGE

Reader - Also called an interrogator. The device that contains the "radiotronics" which trigger the transponder to respond. The reader is a device that captures and processes tag data then passes the digital data to a computer system. The readers main functions are; supply power to passive tags, provide command data to tags, capture returned tag signals and process into a digital bit stream, output data to another output device or to a computer system, and write data to the tag. Readers can be configured with antennas in many formats including handheld devices, portals or conveyor mounted. TOP OF PAGE

Reader Signal Strength - Typically, the read range performance of an RFID system is determined to a major extent by the reader, the power of the signal it radiates, the antenna design and the sensitivity of its receiver. As expected, short range RFID reader systems, tend to be less expensive and easier to design/build, as compared to a long range system. TOP OF PAGE

Read-Write Tags - RFID chips that can be read and written to multiple times. Read-Write tags can accept data at various points along the distribution cycle. This may include transaction data at the retail point of sale. They are typically more expensive than read-only tags but offer more flexibility. TOP OF PAGE

RFID Shielding - Device used to place RFID-enabled cards or passport in, to shield their data from being read from someone just passing by them with a portable reader. TOP OF PAGE

RFID Transponder - Another name for a RFID tag. Typically refers to a microchip that is attached to an antenna, which communicates with a reader via radio waves. RFID tags contain serial numbers that are permanently encoded, and which allow them to be uniquely identified. RFID tags vary widely in design. They may operate at one of several frequency bands, may be active or passive and may be read-only or read-write. TOP OF PAGE

S

Serialized Global Trade Item Number (SGTIN) - The Serialized Global Trade Item Number is a new identity type based on the EAN.UCC Global Trade Item Number (GTIN). A GTIN by itself does not represent a pure EPC identity because it does not uniquely identify a single physical object. Instead a GTIN identifies a particular class of object, such as a particular kind of product or SKU. TOP OF PAGE

Smart Label - A label that contains an RFID chip and antenna. These labels can store information such as a unique serial number and communicate with a reader. TOP OF PAGE

T

Tag - a device which is attached to the object to be identified and when appropriate radio signals are received transmits information as radio signals to a reader. Tags are specified according to their operating frequency, memory modes, memory size, type and packaging. TOP OF PAGE

Tag Collision - Interference caused when more than one RFID tag sends back signals to the reader at the same time. The majority of RFID chips incorporate a anticollision function in their circuitry that allows many tags - up to 200 in the case of UHF tags - to be read simultaneously in the reader field. TOP OF PAGE

Transponder - A contraction of the words transmit and respond. This is another name for an RFID Tag. A transponder consists of an RF integrated circuit, the antenna and the substrate. The transponder receives the power it requires to transmit & respond when it placed in an energy field, from radio waves being transmitted by a RFID reader. TOP OF PAGE

U

Ultra-High Frequency (UHF; 860 to 960 MHz) - Ultra-high frequency radio band allocated for RFID use. (902 to 928 MHz in the USA & 860 MHz in Europe) UHF RFID can send information faster and farther than high and low frequency tags. UHF RFID is gaining industry support as the bandwidth of choice for inventory tracking applications including pallets and cases. UHF RFID features larger tags and readers with the longest read distances (2-3 feet with handheld readers and more than 10 feet with portal readers). TOP OF PAGE

W

"WORM" Chip (Write Once Read Many) - The chips memory can be written to once and then becomes "Read-Only" afterwards. TOP OF PAGE