Active Tags

Tags which use batteries as a partial or complete source of power. They are further differentiated by separating them into those with replaceable batteries and those which have the batteries inside a sealed unit or what may be termed unitized active tags.


The ability to address bits, fields, files or other portions of the storage in a tag.


The orientation of the tag to the reader in pitch, roll, and yaw.


Antennas are the conductive elements which radiate, and/or receive energy in the radio frequency spectrum, to and from the tag.


Capable of operating in either of two directions which are the opposite of each other. For example, a tag which can be read or written from either side is bi-directional.


The number of bits or bytes that can be programmed into a tag. This may represent the bits accessible to the user or the total number including those reserved to the manufacturer e.g. parity or control bits.

Capture Window/Field

Region of the scanner field in which a tag will operate.

Closed Systems

A system in which relevant data regarding the attributes of the object is stored in a common data base, accessible via data link by referencing the individual ID code. It usually refers to a system under the control of a single owner or authority.

Code Plate

See Tag


See Multiplexer

Electromagnetic Coupling

Systems which in use a magnetic field as a means of transferring data or power are said to use a electromagnetic coupling.

Electronic Label

See Tag

Electrostatic coupling

Systems which use the inducing of a voltage on a plate as a means of transferring data or power are said to use electrostatic coupling.


Any operation or data which is not in accord with the design or input to the system.

Error Correcting Code (ECC)

Supplemental bits in a data transfer used in conjunction with a polynomial algorithm, in order to compute the value of missing or erroneous data bits (e.g. for a 32 bit data transmission, 7 additional bits are required.)

Error Correcting Mode

Mode of data communication in which missing or erroneous bits are automatically corrected.

Error Correcting Protocol

The rules by which the error correcting mode operates.

Error Management

Techniques used to ensure that only correct information is presented to the user of the system.

Error Rate

The number of errors per number of transactions.


The electronics which drive an antenna are called the exciter or transmitter. Together with the antenna they are called a scanner.

Expansion Port

A plug accessing additional 1/0 capability on a computer or peripheral device.

Factory Programming

The programming of information into a tag occurring as part of the manufacturing process resulting in a read only tag.

Field Programming

Programming information into the tags may occur after the tag has been shipped from the manufacturer to an OEM customer or end user or in some cases to the manufacturer's distribution locations. Field programming usually occurs before the tag is installed on the object to be identified. This approach enables the introduction of data relevant to the specifics of the application into the tag at any time; however, the tag would typically have to be removed from its object. In some cases, change or duplication of all data in the tag is possible. In other cases, some portion is reserved for factory programming. This might include a unique tag serial number, for example.

Field Protection

The ability to limit the operations which can be performed on portions or fields of the data stored in a tag.

Flat Panel Antenna

Flat, conductive sheet antennas, usually made of metal plate or foil.


The number of times a signal executes a complete excursion through its maximum and minimum values and returns to the same value (e.g. cycles).

I.D. Filter

Software that compares a newly read ID with those in a data base or set.

Inductive Coupling

Systems which use the inducing of a current in a coil as a means of transferring data or power are said to use inductive. coupling.

In Use Programming

Many applications require that new data or revisions to data already in the tag, be entered into the tag, while it remains attached to its object. The ability to read from and write data to the tag while attached to its object is called in-use programming. Tags and systems with this capability are called read/write tags and systems.


See Reader and Programmer


Functional period within which no maintenance, adjustment or repair is to be reasonably expected.

Memory Cards

A read/write or reprogrammable tag in credit card size

Memory Modules

A read/write or reprogrammable tag


A condition that exists when the data presented by the reader is different from the corresponding data in the tag.

Mobile Inventory Vehicle

Vehicle equipped with a system for locating tagged vehicles, containers, and other objects for the purpose of inventory control.


The methods of modulating or altering the carriers in order to carry the encoded information are quite varied. They include amplitude modulation (AM)/ phase modulation (PM), frequency modulation (FM), frequency shift keyed (FSK), pulse position (PPM), pulse duration (PDM) and continuous wave (CW). In some cases, different modulating techniques are used in each direction (to and from the tags).

Modulation, amplitude (AM)

Data is contained in changes in amplitude of the carrier.

Modulation, phase (PM)

Data is contained in the changes in the phase of the carrier.

Modulation, frequency (FM)

Data is contained in the changes in the frequency of the carrier.

Modulation, frequency shift keyed (FSK)

Data is contained in the changes between two frequencies of carrier.

Modulation, pulse duration (PDM)

Data is contained in the duration of pulses.

Modulation, pulse position (PPM)

Data is contained in the position of pulses relative to a reference point.

Modulation, continuous wave (CW)

Data is contained in a carrier which is switched on and off.

Multiplexer (multiplexor)

A device which supports multiple scanners or antennas by checking each in accordance with some scheduling scheme which may be either round robin or priority based. This reduces the total amount of electronics in the system at the expense of having all scanners being "blind" part of the time. These devices are called multiplexers or multichannel readers or just controllers.


The value at which a system is designed assure optimal operation. Tolerance consider the "normal" deviation of variable factors.

Nominal Range

The range at which a systems can assure reliable operation, considering the normal variability of the environment in which it is used.


Capability of a tag to operate in any orientation.

Open Systems

Application in which reader/writers do not have access to a common data base.


Alignment of the tag with respect to the scanner, measured in pitch, roll, and yaw.

Orientation Sensitivity

The degree range is decreased by nonoptimal orientation.

Passive Tags

Passive tags contain no internal power source. They are externally powered and typically derive their power from the carrier signal radiated from the scanner.

Port Concentrator

A device that accepts the output from a number of communication interfaces and introduces them into a communication network.

Power Levels

Levels of power radiated from a scanner or tag, usually measured in volts/meter.


Adding or altering in a tag.


In order to be identifiers of specific objects, tags must at some point have their identity and/or other data entered into them. This capability is called programmability.


Some tags which can have their contents changed by a set of electronics in close proximity or in electrical contact with it. Those electronics and their packaging are called a programmer.

Projected Life

This is defined in terms of number of read and/or write cycles, or in active tags this may include shelf life.

Proximity sensor

A device that detects and signals the presence of a selected object at or near the sensor's location.


Systems which communicate over a radio link between a host computer and a data source e.g. keyboards, data terminals, readers for OCR, Bar Codes, Mag Stripes, RF/ID etc. RF/DC enhances the capabilities of Automatic ID Systems by providing the capabilities of hard wired data communications without the physical restrictions interconnecting wires.


Systems that read or write data to RF tags that are present in a radio frequency field projected from RF reading/writing equipment. Data may be contained in one (1 ) or more bits for the purpose of providing identification and other information relevant to the object to which the tag is attached. It incorporates the use of elect romagnetic, or electrostatic coupling in the radio frequency portion of the spectrum to communicate to or from a tag through a variety of modulation and encodation schemes.


Radio Frequency Automatic Identification Systems


The distance at which successful reading and/or writing can be accomplished.


The decoding, extraction and presentation of data from formatting, control and error management bits sent from a tag.

Read Only

See Factory Programming


The ability to extract data under less than optimal conditions.

Read Rate

The maximum rate at which data can be read from a tag expressed in bits or bytes per second.


Many applications require that new data or revisions to data already in the Tag, be entered into the Tag, while it remains attached to its object. Tags with this capability are said to be reprogrammable and are called read/write tags, memory cards or memory modules.


The device containing the digital electronics which extract and separate the information from the format definition and error management bits. The digital electronics perform the actual reading function. These read electronics may also interface to an integral display and/or provide a parallel or serial communications interface to a host computer or industrial controller.


The set of electronics can change the contents of tags while they remain attached to their object are called a reader/writer. (See also reader).


Many applications require that new data or revisions to data already in the tag, be entered into the tag, while it remains attached to its object. The ability to read from and write data to the tag while attached to its object is called in-use programming. Tags with this capability are said to be re-programmable and are called read/write tags, memory cards or memory modules.


Surface Acoustic Wave. A technology in which radio frequency signals are converted to acoustic signals in a piezolectric crystalline material. Variations in phrase shift ion the reflected signal can be used to provide a unique identity.


The antenna's, transmitter (or exciter) and receiver electronics integrated in a single package called the scanner. They may be combined with additional digital electronics including a microprocessor in a package called a reader.


A device that responds to a physical stimulus and produces an electronic signal. See Scanner.


Operational distance between two tags.

Signaling Technique

A complete description of the modulation, encodation, protocol, and sequences required to communicate between two elements of a system.


The rate at which something occurs.


The transmitter/receiver pair or transceiver plus the information storage mechanism attached to the object is referred to as the tag, transponder, electronic label, code plate and various other terms. Although transponder is technically the most accurate, the most common term and the one preferred by the Automatic Identification Manufacturers is tag.


See Tag


To assure that the intended operation was correctly performed.


The transfer of data to a tag, the tags internal operation of storing the data and it may include reading the data in order to verify the operation.

Write Rate

The rate at which information is transferred to a tag, written into the tag's memory and verified as being correct. It is quantified as the average number of bits or bytes per second in which the complete transaction can be performed.

Source: Association for Automatic Identification and Mobility