RFID Glossary
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A
Active tag:
Active tags have an internal battery to power them and an active transmitter to transmit data. Some active tags contain replaceable batteries for years of use; others are sealed units. Active tags generally can transmit data over a longer distance, are considerably larger than passive tags, and have a limited operational lifespan. They are generally used for tracking expensive items over long ranges.
Addressability:
The ability to address bits, fields, files or other portions of the storage in a tag.
Agile reader:
An RFID reader that can read tags operating at different frequencies and/or using different protocols to communicate between the tags and readers
Air Interface Protocol:
The standards that define how RFID tags and readers communicate using radio waves.
Alignment:
The orientation of the tag to the reader in pitch, rolls, and yaws.
(See orientation.)
American National Standards Institute (ANSI):
American technical standards
body that also represents United States to the International Organization
for Standardization.
Amplitude:
The maximum absolute value of a periodic, trigonometric sine curve measured along its vertical axis.
Amplitude modulation:
A method of transmitting information by varying (modulating) the amplitude of the carrier wave.
Amplitude shift keying:
A method of transmitting information using various
levels of amplitudes of a sinusoidal wave. For a digital system, two amplitude. levels are usually used: a level to represent a digital one and a lower level to represent
digital zero. This is a special case of amplitude modulation.
Antenna:
A conductive element that permits the tag to exchange data with the
reader. Passive RFID tags make use of a coiled antenna that can create a magnetic field using the energy provided by the reader’s carrier signal. UHF tag antennas come in a variety of shapes. Readers also have antennas that are used to emit radio waves. The RF energy from the reader antenna is “harvested” by the tag antenna and used to power up the integrated circuit, which then changes the electrical load on the antenna to reflect back its own signals. A transducer made of a conductive material that converts alternating current (AC) supplied through antenna’s feed line to radio waves and also converts received radio waves to AC. Radio waves radiate outward from the antenna. RFID systems use two types of antennas: one connected to the reader and another on the tag.
Antenna gain:
The ratio of the amount of energy radiated in one direction and
the energy radiated by a reference antenna in the same direction when driven by
the identical input. Gain is generally specified in decibels (dB). Usually we are
interested in the maximum gain—the direction in which the antenna is radiating
the most power.
Anti-collision:
In the context of RFID, refers to different ways of keeping radio
waves from one tag from interfering with radio waves from another tag.
Anti-collision algorithm is used to collect data frommultiple RFID tags present
at the same time in a reader’s interrogation zone without interference.
Association for Automatic Identification and Mobility:
A trade association of
companies that globally provide products and services related to automatic identification,
data collection, networking, and information management systems.
ATR (Answer To Reset):
A data string returned by a smart card when it is
powered on.
Attenuation:
Reduction of RF energy from an RFID tag or reader; water absorbs
UHF energy, causing signal attenuation.
Attenuator:
A device that attaches to a transmission line and reduces the
power of the RF signal as the signal travels through the cable fromthe reader to
the antenna. Attenuators usually work by dissipating the RF energy into heat.
Authentication:
A method to prevent fraud with contact, dual interface and contactless smart cards by ensuring that only a read/write unit and a smart card, belonging to the same service, can communicate with each other.
Auto-ID Center:
A non-profit collaboration between private companies and
academia that pioneered the development of an Internet-like infrastructure to
track goods globally through the use of RFID tags carrying Electronic Product Codes. The center closed its doors in September 2003. The organization
EPCglobal now continues this work.
Auto-ID Labs:
Nonprofit research labs, headquartered at the Massachusetts
Institute of Technology, that continue to performprimary research into the development
of Electronic Product Code (EPC) and related technologies.
Automatic Identification:
A broad term used for the methods of
collecting data and entering it into computer systems without human involvement.
Technologies normally considered part of Auto-ID include barcodes,
biometrics, RFID, and voice recognition.
Automatic identification and data capture:
A broad term that covers
methods of identifying objects, capturing information about them, and entering
it directly into computer systems without human involvement.
Auto-Talking:
A transponder is auto-talking when it starts sending its memory
content as soon as it enters an RF field froma read/write unit, without the need
of a special command.
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B
Back channel:
Communication method used by the signal returning from the
RFID tag back to the interrogator.Also known as reverse channel or reverse link.
Backscatter:
A method of communication by which a tag reflects the carrier
wave received fromthe interrogator. To transfer information, the tag modulates
the amplitude of the reflected wave. Passive and semi-passive tags use this
method to send information to the interrogator.
Bar code:
A way of encoding information using black-and-white stripes or
patches. Stripes are used by linear barcodes and patches are used by two-dimensional
barcodes. The most common barcode is Universal Product Code (UPC)
used on most grocery and retail items. Barcodes are read using laser scanners
and require a line-of-sight.
Base station:
An electronic device made up of an RF transmitter, a receiver,
and an antenna. It is used to communicate with RFID transponders and
contactless smart cards. It connects systems such as access control terminals,
ticket vending machines, and car immobilizer units to host computers.
Battery-assisted tag (BAT):
An RFID tag that has a battery but does not have an active transmitter. It communicates using the same backscatter technique used by passive tags. It uses the battery to run the circuitry on the integrated circuit and sometimes an onboard sensor. BATs have a longer read range than passive tags. They are sometimes called semi-passive RFID tags or battery assisted passive (BAP) tags.
Baud:
In a digitally modulated signal, baud measures symbol rate: that is, the
number of distinct symbol changes (signaling events) made to the transmission
medium per second. The baud rate is not the same as bit rate because one symbol
may carry more than 1 bit of data. Sometimes many symbols are used to
convey 1 bit of data.
Beacon:
An active RFID tag that is programmed to wake up and broadcast its
signal at set interval.
Bi-directional:
RFID tags that are bi-directional are able to operate (that is, be read or be written to) from the front or from the back.
Bi-static Reader:
An interrogator that uses two antennas to interrogate the tags: one to transmit the signal and another to receive. The two antennas, transmit (Tx) and receive (Rx), form one interrogation port. An interrogator may have one or more such ports.
BNC connector:
A male type of connector used with coaxial cables. It has a
center pin connected to the center conductor and ametal tube connected to the
outer cable shield. An outer rotating ring is used to lock the cable to a female
connector. It was named after its bayonet mount locking mechanism and its two
inventors Neill and Concelman. Over the years it has picked up other names
such as bayonet navy connector, baby N connector, barrel nut connector, bayonet
nipple connector, British naval connector, and British national connector.
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C
Capacitor:
An electric circuit element used to store a charge temporarily.A capacitor
usually consists of twometallic plates separated and insulated fromeach
other by a dielectric substance.
Capacity:
The amount of information that can be programmed into a tag or the bits accessible to the user or the total number including those reserved to the manufacturer e.g. parity or control bits.
Card operating system:
The software program stored in the smart card IC
that manages the basic functions of the card, such as communication with the
terminal, security management, and data management in the smart card file
system.
Carrier frequency:
The base or central frequency of a sinusoidal wave used to
carry (transmit) information using radio waves, electric current through wires,
or light waves through optical fibers. This frequency is modulated by varying its
amplitude, frequency, or phase to carry information.
Checksum:
A code added to the contents of a block of data stored on an RFID
integrated circuit that can be checked before and after data is transmitted from
the tag to the reader to determine whether the data has been corrupted or lost.
The cyclic redundancy check is one form of checksum.
Chip:
See Integrated Circuit.
Chipless RFID tag:
A chipless RFID tag (also known as RF fibers) does not use integrated circuit technology to store information. The tag uses fibers or materials that reflect a portion of the reader’s signal back; the unique return signal can be used as an identifier. The fibers are shaped as thin threads, fine wires, or labels or laminates. Chipless RFID tags can be used in environments that differ fromthose with RFID tags with electronic circuitry. They tend to work over a wider temperature range, and they are less sensitive to RF interference. Chipless tags are sometimes used in anti-counterfeiting with documents. However, since the tags cannot transmit a unique serial number, they are less usable in the supply chain.
Circularly-Polarized Antenna
An antenna whose plane of polarization rotates in a circle, making one revolution during the time it takes the radio wave to travel the distance of one wavelength. If the rotation is clockwise, looking in the direction of propagation of wave, the sense is called right-hand-circular (RHC). If the rotation is counterclockwise, the sense is called left-hand-circular (LHC). These antennas are used when the orientation of the tag to the reader cannot be controlled. They provide shorter read range than the linearly polarized antenna because only half the radio energy is transmitted in any one plane at a time. Code Plate:
Another term for an RFID tag.
An RFID tag is a microchip combined with an antenna in a compact package; the packaging is structured to allow the RFID tag to be attached to an object to be tracked.
Closed-loop systems:
RFID control systems in which the tracked objects never leave the company or organization; the objects either stay within one organization or circulate among a small known group of organizations. All the data related to the object is usually stored in one place, so the complete history of the object is readily available. The usual concerns about RFID standards do not apply, since the tracked object does not leave the system. This type of systems is somewhat easier to implement because of the controlled set of variables. Although closed-loop systems may be implemented without concerns for RFID standards, it is a good practice to follow prevailing industry standards in system design.
Collaborative planning, forecasting and replenishment:
A general termused
to describe cooperation between manufacturers and retailers to match supply of
goods with demand for them.
Commissioning a tag:
The process of writing data to the tag for the first time.
The data may include only an identifying number or a number and other information
and may be written to a tag during tag manufacturing or when the tag is
attached to the object. In most RFID systems, this data is associated with information
about the object stored in database.
Compatibility:
Two systems are considered compatible if they are equal in interface
specifications, such as protocols, frequencies, and voltage levels, and are
thus able to operate together. (See interoperability).
Concentrator:
A device connected to several RFID readers that gathers data
from the readers. It performs some filtering and then passes on only useful information
from the readers to a host computer.
Contactless smart card:
The term contactless smart card refers to identification cards (for example, some credit cards) that do not need to make contact with the reader to be read, or swiped in a special slot. This capability is implemented using a tiny RFID tag in the card; the intent is to provide the user with greater convenience by speeding checkout or authentication processes.
Contactless credit card:
Unlike an ordinary credit card, a contactless credit
card uses RFID technology to store information about an account and to transfer
it to the merchant. Standard credit cards carry data on a magnetic strip;
when the card is swiped against a reader, the data is transferred. The primary advantage
of contactless cards lies in the speed of the transaction.
Continuous Wave:
A means of communication between an RFID tag and a reader; the data is contained in pulses of the carrier wave sent out by the reader.
Controller:
See Multiplexer
Coupling:
See inductive coupling.
Cyclic redundancy check (CRC):
A method of checking data stored on an
RFID tag to be sure that it hasn’t been corrupted or lost. (See checksum.)
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D
Data Carrier
A medium that is capable of holding data, such as RFID tags,
barcodes, and magnetic strips.
Data Field
The smallest subdivision of RFID integrated circuit memory that is
used to store a particular type of information, such as a product number or an
access password.
Data Field Protection
The ability of an RFID integrated circuit to prevent data
stored in a data field from being overwritten.
Data Transfer Rate
The number of bits or bytes of data that can be transferred
between an RFID tag and a reader per unit of time.
dB
See decibel.
dBm
Unit of power specified in decibel relative to 1 milliwatt.
dBw
Decibel watt (dBW) is a unit for the measurement of the strength of a signal expressed in decibels relative to one watt.
Detune
When RFID tags are attached to metal or are present in vicinity of metal, the performance of the RFID antenna gets reduced, i.e. the antenna gets detuned.
Dead Tag
An RFID tag that cannot be read by an RFID reader due to a fault in
the tag.
Decibel
A unit used to express ratio of two quantities, usually power. Decibel
is one tenth of a Bel—a log of ratio of two quantities. Antenna gain and cable
losses are specified in decibel.
Detune
When RFID tags are attached to a conductive material or are in the vicinity
of such material, the property of the antenna on the tag changes. This
causes the antenna to be tuned to a different frequency than the intended design
frequency. The antenna is said to be detuned from its intended frequency.
Die
Silicon disk on which integrated circuits are created.
Dielectric
A material that is a poor conductor of electricity, but an efficient supporter of electrostatic fields. Some examples of dielectric include porcelain (ceramic), mica, glass, plastics, oxides of various metals, dry air, and distilled water. Dielectrics are used in RF transmission lines. In a coaxial cable, polyethylene, a dielectric, is used between the center conductor and outside shield.
Dielectric Constant
Also called relative permittivity. A number that relates the
ability of a material to carry alternating current to the ability of a vacuum to carry
the same. The dielectric constant of a material affects howelectromagnetic signals
(light, radio waves)move through the material.Ahigh dielectric constant detunes
an RFID antenna and reduces the performance of an RFID tag.
Digital Certificate
An attachment to an electronic message used for security
purposes. It verifies the authenticity of a user sending a message and provides
the receiver with the means to encode a reply. An individual wishing to send an
encrypted message applies for a digital certificate from a certificate authority,
which issues an encrypted certificate containing the applicant’s public key and a
variety of other identification information.
Digital Signal Processor
A specialized microprocessor designed specifically
for digital signal processing. It is used in RFID readers.
Digital Signature
An electronic signature that can be used to authenticate the
identity of the sender of a message or the signer of a document. It also ensures that
the original content of the message or document that has been sent is unchanged.
Digital Signature Algorithm
The Digital Signature Algorithm is a United States government’s standard for creating digital signatures.
Dipole
An antenna made of a straight electrical conductor measuring half the
wavelength fromend to end and connected at the center to an RF feed line. This
is the basic and simplest practical antenna and has gain of 2.2 dBi. It is frequently
used as a base to compare other antennas. Most UHF and microwave
tags have dipole antenna connected to an integrated circuit.
Dual Interface Smart Card
An RFID-enabled card that can be read either
when it comes in contact with a reader or from a distance.
Dumb Reader
An RFID reader that does not have a microprocessor and lacks
data processing capability.
Duplex
A communications system that allows transmission of data in both
directions. Full duplex allows transmission of data in both directions simultaneously.
Half duplex allows transmission of data in both directions, but not simultaneously.
Duty Cycle
The percentage of the time the reader is allowed to transmit RF
signals within a specified time slot.
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E
EAN
See European Article Numbering.
EAS
See electronic article surveillance.
Edge Server
A computer directly controlling data collection devices and peripherals
in warehouses, distribution centers, and manufacturing plants. This
computer supplies collected data, sometimes after filtering, to enterprise servers.
EDI
See Electronic Data Interchange
EEPROM
See Electrically Erasable Programmable Read-Only Memory.
Effective Isotropic Radiated Power (EIRP)
The amount of power that would
have to be emitted by an isotropic antenna to produce the peak power density
observed in the direction of maximum antenna gain. EIRP generally takes into
account the losses that occur in transmission lines and connectors and the gain
of the antenna. EIRP is used by many regulating authorities to specify maximumallowable
power froman antenna. It is sometimes referred to as equivalent
isotropically radiated power.
Effective Radiated Power (ERP)
The power necessary at the input terminals
of a reference half-wave dipole antenna to produce the same maximum field intensity.
It is a product of the power supplied to the antenna and antenna gain
relative to a half-wave dipole in a given direction, usually in the direction of
maximum gain.
EIRP
See effective isotropic radiated power.
Electrically Erasable Programmable Read-Only Memory (EEPROM)
Read-only memory that can be erased and reprogrammed repeatedly through
the application of higher than normal electrical voltage. RFID tags that use EEPROMaremore expensive than factory programmed tags that cannot be reprogrammed.
Electromagnetic Interference (EMI)
Interference caused by radio waves of various RF-emitting devices such as cell phones, cordless phones, and microwaves.
EMI reduces the performance of an RFID system.
Electronic Article Surveillance (EAS)
A method of preventing unauthorized
removal of articles from an area. The system consists of gate antennas, readers,
and EAS tags. Tags are attached to the articles being monitored. This system is
widely used to prevent shoplifting in retail stores and pilferage of books fromlibraries.
The tags are turned off by the staff when items are properly removed. If
a tagged-itemis removedwithout tag being deactivated, the detection systemlocated
at the exit reads the tag and sounds an alarm or alerts the staff.
Electronic Data Interchange (EDI)
A method of transmitting electronic data
in a standardized format.
Electronic Pedigree
Collection of data about the movement of product
through supply chain, which helps prevent product counterfeiting.
Electronic Product Code (EPC)
See electromagnetic interference.
EMI
See Electromagnetic Interference
Encryption
A method of scrambling information to make it unreadable to
those who are not authorized to read it. In an RFID system, encryption prevents
readers that are not part of the system from reading information stored
on RFID tags.
Enterprise Resource Planning (ERP)
A business management multi-module
software system that integrates (or attempt to integrate) all facets of the business,
including planning, manufacturing, sales, and marketing into a unified
system. It integrates business activities such as product planning, purchasing,
inventory control, order tracking, customer service, finance, and human resources.
All information is saved in a relational database system. The deployment
of an ERP system can involve considerable business process analysis,
employee retraining, and new work procedures.
EPC
See Electronic Product Code.
EPC Discovery Service
As a part of EPCglobal network, allows users to find
data related to a specific Electronic Product Code.
EPC Generation 2
The standard ratified by EPCglobal for the air interface
protocol for the second-generation of EPC technologies.
EPC Information Service
A specification for a standard interface for accessing
Electronic Product Code–related information from EPCglobal network. It
allows companies to store EPC data in secure databases on the Web.
EPCglobal Inc.
A non-profit organization set up by the Uniform Code
Council and EAN International, the two organizations that maintain barcode
standards, to commercialize EPC technology. EPCglobal is leading the development
of industry-driven standards for EPC to support the use of RFID.Uniform
CodeCouncil andEANInternational are nowpart of organization called GS1.
EPCglobal Network
A set of specifications that allows companies to collect,
store, and retrieve data associated with Electronic Product Codes.
EPROM
See erasable, programmable, read-only memory.
Erasable Programmable Read-Only Memory
Nonvolatile memory
that can be erased by exposing it to ultraviolet light and reprogrammed.
Error Correcting Code
Code stored on an RFID tag that enables localization
and correction of errors.
Error Correcting Mode
Automatically detects and corrects errors in the data
transmission between tags and readers.
Error Correcting Protocol
Readers use error correcting protocol to interpret data correctly from tags.
ETSI
See European Telecommunications Standards Institute.
European Article Number
An industry organization that develops
and maintains barcoding standards for product identification.
European Telecommunications Standards Institute
An independent,
non-profit telecommunications standards organization whose work is carried
out by technical working groups consisting of telecommunications companies,
manufacturers, regulatory authorities, and other parties in the sector.
Excite
An RFID reader excites (powers up) a passive tag by sending radio waves
toward it. The tag responds by transmitting a radio signal toward the reader.
eXtensible Markup Language
A general-purpose language used to
share information over the Internet.
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F
Factory Programming
The information on some read-only tags is written in
the factory where they are manufactured. Such tags cannot be reprogrammed.
False Read
See phantom read.
Far-Field Communication
If an RFID tag is outside of one fullwavelength of the
reader, it is said to be in the far field. The far-field signal decays as the square of the
distance from the antenna. The far-field signal is typically used in ultra high frequency
(UHF) and microwave systems. See also near-field communication.
Field Programming
Writing data to the tag after it has been manufactured.
These tags use EEPROM memory that can be erased and reprogrammed many
times.
Firmware
Software that is embedded in a hardware device. A computer program
in a read only memory (ROM) integrated circuit.
Flash memory
A form of nonvolatile computer memory that can be electrically
erased and reprogrammed in blocks instead of 1 byte at a time.
Fluidic Self Assembly
Fluidic self assembly is a patented manufacturing assembly technology from Alien Technology that enables efficient placement of very large numbers of small components across a surface in a single operation. The technology has enabled Alien Technology to offer low cost RFID tags.
Folded Dipole
A dipole antenna in which the poles are connected to each
other as well as to the integrated circuit.
Form Factors
The different forms in which RFID tags are available, including
smart labels, plastic cards, key fobs, and so on.
Forward Channel
The path of transmission of radio waves from the RFID
reader to the RFID tag.
Free Air
Reading of an RFID tag that is not attached to an item.
Frequency
The number of occurrences of a repeated event per unit time,
measured in hertz (Hz). RFID systems use low, high, ultra high, and microwave
frequencies.
Frequency Hopping
A technique to prevent RF devices operating in the same
frequency range from interfering with one another.
frequency shift keying (FSK)
A modulation technique involving two different
frequencies used in digital signals. The two binary states, logic 0 (low) and 1
(high), are each represented by an analog waveform. Logic 0 is represented by a wave at a specific frequency, and logic 1 is represented by a wave at a different
frequency.
FSK
See frequency shift keying.
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G
GCI
See Global Commerce Initiative.
GDS
See global data synchronization.
Gen 2
See EPC Generation 2.
GLN
See global location number.
Global Commerce Initiative (GCI)
A user group that brings manufacturers
and retailers together on a worldwide parity basis to simplify and enhance
global commerce and improve consumer value in the overall retail supply chain.
Global Data Synchronization (GDS)
A process of ensuring accuracy of product
information among various supply chain partners such as manufacturers
and retailers.
Global Location Number (GLN)
A 13-digit number used to identify parties and
their locations uniquely in electronic commerce transactions and encoded in a
barcode or an RFID tag.
Global Positioning System (GPS)
Satellite navigation system that transmits
signals allowing GPS receivers to determine the receiver’s location, speed, and
direction. It is an important tool for map-making and land surveying.
Global System for Mobiles (GSM)
A digital mobile telephone system that is
widely used in various parts of the world. It operates on the 900-megahertz and
1.8-gigahertz bands in Europe, where it is the predominant cellular system, and
on the 1.9-gigahertz band in the United States.
Global Trade Item Number (GTIN)
Used for identifying trade items and is developed
by GS1. Product identification numbers, such as EAN/UCC-8,
UCC-12, EAN/UCC-13, and EAN/UCC-14, are drawn fromthe worldwide system
of GTIN.
GPS
See global positioning system.
Ground Plane
An electrically conductive surface that may be natural, such as
earth or ocean; an available artificial surface, such as vehicle body; or a specially designed artificial surface, such as large conductive metal plate found in most
antennas. The ground plane should extend a minimum of one wavelength
(preferably more) in each direction from the antenna.
GS1
SGS1 is a leading global organization dedicated to the design and implementation
of global standards and solutions to improve the efficiency and visibility
of supply and demand chains globally and across sectors.
GSM
See Global System for Mobiles.
GTAG
See Global Tag
GTIN
See Global Trade Item Number.
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H
Harvesting
A technique in which energy froman RFID reader is gathered by a
passive RFID tag.
High Frequency (HF)
A frequency range between 3 and 30 MHz. In RFID systems,
only 13.56 MHz is used out of the entire HF range.
Host System
A networked computer that provides services to other computers
or users in that network.
Hybrid Card
A card with two chips—one with a contact interface and one
with a contactless interface; unlike a dual-interface card,which has a single chip
with both contact and contactless interfaces.
Hysteresis
When a tagged object absorbs water and then dries, the performance of the RFID tag is reduced. This effect is known as hysteresis.
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I
I/O Ports
See input-output ports
IC
See integrated circuit.
Inductive Coupling
The transfer of energy from one circuit to another by
means of mutual inductance between the two circuits. Some RFID tags and
readers exchange information using inductive coupling between their antennas.
Low-frequency and high-frequency RFID systems use inductive coupling.
Industrial, Scientific, and Medical bands (ISM)
Radio frequency ranges
(902–928, 2400–2483.5, 5725–5850 MHz) originally reserved internationally
for non-commercial use by the industrial, scientific, and medical (ISM) organizations.
In recent years they have also been shared with license-free error-tolerant
communications for commercial applications such as wireless LANs and
Bluetooth.
Inlay
Also known as inlet, it consists of an integrated circuit, an antenna, and
a substrate. It is the main component of an RFID tag and smart label.
Inlet
See inlay.
input/output ports (I/O ports)
Ports on an RFID reader that can be connected
to external devices.
integrated circuit (IC)
A small electronic circuit that is created on the surface
of a thin substrate of a semiconductor.
Intelligent Reader
A reader that incorporates an embedded computer system
that can filter the data collected from the RFID tags, control peripheral devices,
and execute commands, unlike a dumb reader that can only retrieve data from
RFID tags.
Intentional Radiator
A device that produces radio waves on purpose, including
RFID transmitters.
International Organization for Standardization (ISO)
A non-governmental
organization made up of the national standards institutes of 146 countries that
produces world-wide industrial and commercial standards.
Interoperability
The ability of RFID tags and readers from different vendors
to operate in an RFID system.
Interconnection
A device that connects an RFID integrated circuit to an antenna
on an RFID tag.
Interposer
A device that connects an RFID microchip to an antenna in an RFID tag.
Interrogation Zone (IZ)
The space in which an RFID tag can receive a radio
signal from a reader. For a passive tag the signal should be strong enough to
power the tag, while for a semi-passive tag it should be strong enough to raise
the tag’s backscattered signal above noise floor.
Interrogator
See Reader.
I/O Ports
See input/output ports.
ISM
See Industrial, Scientific, and Medical bands.
ISO
See International Organization for Standardization.
ISO 7816
An international standard for smart cards.
ISO 10536
An international standard for contactless integrated circuit cards.
ISO 11784 & 11785
International standards that regulate the radio frequency
identification of animals in regards to code structure and technical concept.
ISO 14443
Defines international standards for a proximity card used for identification
that usually uses the standard credit card form factor.
ISO 15693
Defines international standards for vicinity cards.
ISO 18000
Aseries of RFID air interface standards for the itemidentification.
Isotropic Antenna
An antenna that emits energy equally in all directions. A
theoretical concept for which no physical antenna can be made.
Item-Level Tagging
Using RFID tags to track individual items throughout the
supply chain.
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L
Linearly-Polarized Antenna
An antenna that emits energy from the reader wholly in one plane containing the direction of propagation.
Low Frequency (LF)
Low frequencies range from 30 to 300 KHz. Low-frequency
RFID systems usually operate at only one of two frequencies—125 kHz
or 134 kHz.
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M
Memory Block
Data stored on an RFID integrated circuit is divided into different
sections known as memory blocks. Each memory block can be individually
read from and written to, and can be locked to prevent it from being
overwritten.
Memory Capacity
The amount of data that can be stored on an RFID integrated
circuit.
Microcontroller
A tiny computer on a chip. It is a single integrated circuit
comprising a central processing unit, input/output interfaces such as serial
ports, peripherals, RAM for data storage, and ROM, EPROM, EEPROM, or
Flash memory for program storage.
Microprocessor
A single integrated circuit that contains a CPU and some
form of memory.
Microwave
Electromagnetic waves that range between 1 GHz and 300 GHz
frequencies. RFID systems use only two frequencies—2.4 and 5.8 GHz.
Middleware
In an RFID system, a set of software modules that collects data from RFID readers, controls and monitors RFID readers and peripherals, and filters information received from RFID readers. The information is then passed to the enterprise applications. Middleware act as conduit between the edge devices and business applications such as factory and warehouse management systems.
Modulation
The process of modifying the carrier wave to transmit information.
Various types include amplitude modulation, phase modulation, frequency
modulation, and pulse-width modulation.
Monostatic Reader
An RFID reader that uses the same antenna to transmit
and receive radio signals.
Multimode
RFID tags that can be programmed to operate according to a number of different standards.
Multiple Access Schemes
Methods of increasing the amount of data that can be transmitted wirelessly within the same frequency spectrum.
Multiplexer
Allows several single antennas and gate solutions to be operated
with only one reader. A device that allows several antennas to be connected to a
single antenna port. Multiplexers are not efficient and economical to use at
higher frequency ranges such as UHF and microwave.
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N
NanoBlock
A small microchip developed by Alien Technology.
National Institute of Standards and Technology
A federal technology
agency whose mission is to promote U.S. innovation and industrial competitiveness
by advancing measurement science, standards, and technology in ways
that enhance economic security and improve quality of life.
Near Field Communication
The tag and reader antenna are coupled
within one full wavelength of the carrier wave. The near-field signal attenuation
is proportional to the sixth power of the distance from the antenna.
NFC
See near-field communication.
Nominal Range
The range at which a tag can be read reliably.
Non-Volatile Memory
Computer memory that can retain stored information
even when the power to it is turned off, such as EPROM, EEPROM, and Flash
Null Spot
A space in the interrogation zone that does not receive a strong
enough radio signal to promote communication between a tag and a reader.
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O
Object Naming Service (ONS)
A subsystem within the EPCglobal Network that provides the location of an EPC Information Service for an Electronic Product Code number. It operates just like a DNS system for Internet access.
OEM
See original equipment manufacturer.
One-Time Programmable
Memory that can be programmed only once; then it
becomes read-only memory.
One-Time Programmable Tag
An RFID tag that can be written to only once
and read many times.
ONS
See Object Naming Service.
Orientation
Alignment of the RFID tag with respect to the reader antenna polarization
plane. To communicate with a reader connected to a linearly polarized
antenna, a tag must have the same orientation as the polarization plane of
the reader antenna. If the reader antenna is circularly polarized, the tag orientation
has no effect.
Original Equipment Manufacturer
An organization that makes products
for others to repackage and sell. Resellers buy OEM products in bulk and
then sell them under the reseller brand..
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P
Passive Tag
An RFID tag that does not contain an on-board power source (a
battery) and an active transmitter. It gets its power fromradio waves emitted by
a reader.
Patch Antenna
An antenna that consists of a square conductor mounted over
a ground plane.
Phantom Read
The phenomenon in which a reader reads a tag that does not
belong to the business process being monitored.
Phase-Shift Keying (PSK)
A method of digital communication in which the
phase of a carrier wave is changed or modulated to convey information..
Physical Markup Language (PML)
A markup language based on XML for
communicating a description of products.
PML
See Physical Markup Language.
PML Server
PML server includes one or more databases in which are stored one or more files containing information regarding the tagged item.
Power Level
The amount of energy emitted by an RFID reader, usually expressed
in watts or dBm.
Private Key
Encryption/decryption key known only to the party or parties
that exchange secret messages.
Programming a Tag
Encoding information on an RFID integrated circuit
Protocol
See air interface protocol.
Proximity Sensor
A device that detects the presence of an object. Proximity
sensors may be of contact or non-contact type.
PSK
See phase shift keying.
Public Key
A publicly available key provided by some designated authority as
an encryption key that, combined with a private key, can be used to encrypt
messages and digital signatures.
Public Key Cryptography
A cryptographic system that uses two keys - a public key known to everyone and a private or secret key known only to the recipient of the message.
Public Key Infrastructure
Public key infrastructure enables users of a basically unsecure public network such as the Internet to securely and privately exchange data and money through the use of public and private cryptographic keys.
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Q
Quiet Tag
An RFID tag that can be read occasionally with the interrogator
output at full power, or that can be read only at very close range.
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R
Radio Frequency Identification
Amethod of identifying objects using
radio waves.Typically, a reader communicates with a tag,which holds digital information
in an integrated circuit. Chipless forms of RFID tags use material to
reflect back a portion of the radio waves beamed at them.
RAM
See Random Access Memory
Random Access Memory
Memory used for temporary storage of data.
Information stored in RAM is lost when power to it is removed.
Read
The process of retrieving data stored on an RFID tag.
Read Field
See Reader Field.
Read Range
The maximum distance at which a reader and tag can communicate.
Read Rate
The number of tags that can be read per unit of time.
Read Only Tag
An RFID tag that can only be read. The data written on its integrated
circuit cannot be changed.
Read Write Tag
An RFID tag that can bewritten to and read frommany times.
Reader
A device that retrieves information written on RFID tags by transmitting
and receiving radio signals to and fromthe tags.Reader also provides power
to passive tags, and most readers can also write data to the tag.
Reader Field
A space within which an RFID tag can be read by the reader.
Reader Talks First
A design in which a reader initiates the communication
with the tag.
Real Time Location System (RTLS)
A system for tracking the location and movement of products in real time using RFID tags and readers.
Reverse Channel
The channel through which a radio signal travels from an
RFID tag to a reader. It is also called return link.
RFID
See Radio Frequency Identification.
RTLS
See real time location system.
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S
Savants
A term used to describe distributed middleware designed by the Auto-ID Center to filter data from EPC readers and pass it on to enterprise systems. The term is being phase out by EPCglobal and many of the functions of Savants are being incorporated in commercial middleware products. It is the primary means of data gathering for any RFID deployment.
SAW
See Surface Acoustic Wave.
Scanner
The antenna's, transmitter (or exciter) and receiver electronics integrated in a single package called the scanner to read a bar code. They may be combined with additional digital electronics including a microprocessor in a package called a reader.
Semi-passive tags
An RFID tag that has on-board power (battery) but no active
transmitter. The battery is used to power an integrated circuit and optional
environmental sensor. Some semi-passive tags sleep until they are awakened by
a signal from the reader, which conserves battery life. These tags are sometimes
called battery assisted tags or battery assisted passive tags.
Sensor
A device that produces an electronic signal in response to something in the environment. Sensors are increasingly being combined with RFID tags to detect the presence of a stimulus at an identifiable location.
Separation
Refers to the distance between two tags or the distance between a tag and a reader.
Signal attenuation
A weakening of a signal as it travels from a transmitter to
receiver.
Signaling Technique
A complete description of the modulation, encoding,
protocol, and sequences required to communicate between two elements of a
system..
Silent Commerce
This term covers all business solutions enabled by tagging,
tracking, sensing, and other technologies, including RFID, that make everyday
objects intelligent and interactive.When combined with continuous and pervasive
Internet connectivity, they form a new infrastructure that enables companies
to collect data and deliver services without human interaction. This type of commerce is “silent” because objects communicate and commerce takes place without human interaction.
Singulation
A method of identifying one tag from a group of tags present in
the reader’s interrogation zone.
Skimming
Reading an RFID tag on a person without his or her knowledge, or
reading a tag surreptitiously.
Slap and ship
Placing an RFID tag on a case or pallet just before it is shipped
from a supplier. Generally used to meet a customer’s mandate. It is also called
tag and ship.
Slotted antenna
An antenna that consists only of a narrow slot cut into an electrical conductor connected to the transponder. Slotted antennas exhibit the same orientation sensitivity as dipoles.
Smart card
Also called chip card or integrated circuit(s) card (ICC). Any
pocket-sized card with embedded integrated circuits.When the card uses RFID
technology to send and receive data, it is called a contactless smart card.
Smart label
A label that usually contains both a traditional barcode and an
RFID tag. As barcodes are printed on smart labels, information is also encoded
into the RFID tag by the printer.
Strap
A tag subassembly where the integrated circuit (IC) is attached to two
large, relative to IC, metallic patches by the IC manufacturer. The strap makes it
easy to attach antenna to IC during tag manufacturing.
Subscriber identity module (SIM)
A Subscriber Identity Module (SIM) is a removable smart card, available in two standard sizes the first the size of a credit card (85.60 mm × 53.98 mm x 0.76 mm), while its more popular mini version has a width of 25 mm, a height of 15 mm, and a thickness of 0.76 mm. It is an essential component of a GSM mobile phone. It contains the identity of the subscriber and assures the authentication during the access into the network and provides data storage for other subscriber related information, such as a personal address books.
Surface acoustic wave
An acoustic wave traveling along the surface
of a material having some elasticity, with an amplitude that typically decays exponentially
with the depth of the substrate. This technology is used for automatic
identification in which low power microwave radio frequency signals are
converted to ultrasonic acoustic signals by a piezoelectric crystalline material in
the transponder.Variations in phase shifts on the reflected signal can be used to
provide a unique identity.
Synchronization
Allocating time slots to the readers located in close vicinity
so they do not interfere with each other.
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T
Tag
See RFID tag.
Tag excitation device (TED)
A term coined by the RFID Alliance Lab for the
device that sends signals to the tag regardless of the make or manufacturer.TED
is used to measure the response of tags scientifically.
Tag Talks First (TTF)
A protocol for exchanges between the reader and the tag,
where the tag sends information continuously, without waiting for a specific
command from the reader.
Time division multiple access
Time division multiple access (TDMA) is a channel access method for shared medium (usually radio) networks. It allows several users to share the same frequency channel by dividing the signal into different timeslots. TDMA is a type of Time-division multiplexing, with the special point that instead of having one transmitter connected to one receiver, there are multiple transmitters.
Track and trace
The process of storing and retrieving information about the
movement and location of objects.
Transceiver
A device that has a transmitter and a receiver; both are combined
and share common circuitry or a single housing.
Transponder
See RFID tag.
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U
Ultra-high frequency (UHF)
Ultra high frequencies range between 300 and
3000 KHz.UHFRFID systems operatewithin a narrowrange of 860 to 960 MHz.
Uniform Code Council (UCC)
The nonprofit organization that overseas the
Uniform Product Code, the barcode standards used in North America.
Unique Identifier (UID)
A globally unique identifying number used by the
U.S. Department of Defense to track objects within its system.
Unitized active tag
An active tag or transponder in which the batteries are replaceable or sealed within the device.
Universal Product Code (UPC)
The barcode standard used in North America
and administered by the Uniform Code Council.
Uplink
It defines the direction of communication from transponder to reader/interrogator.
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V
Vector
A quantitative component that represents magnitude, direction and sense.
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W
WORM
Write once, read many. A tag that can be written once by the user and
thereafter can only be read.
Write
The process of transferring data to a transponder from the reader.
Write rate
The rate at which information is transferred, written into the tag’s
memory, and verified as being correct.
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X
XML
See eXtensible Markup Language.
XML Query Language (XQL)
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.
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