Glosssary - Reader

A generic term that usual refers to an RFID reader that can read tags operating at different frequencies or using different methods of communication between the tags and readers.

The tag antenna is the conductive element that enables the tag to send and receive data. Passive, low- (135 kHz) and high-frequency (13.56 MHz) tags usually have a coiled antenna that couples with the coiled antenna of the reader to form a magnetic field. UHF tag antennas can be a variety of shapes. Readers also have antennas which are used to emit radio waves. The RF energy from the reader antenna is "harvested" by the antenna and used to power up the microchip, which then changes the electrical load on the antenna to reflect back its own signals.

An RFID reader that is connected to a host system.

The process or capability of a radio frequency identification reader/interrogator to read a number of transponders present within the system’s interrogation zone at the same time. Alternative term for Multiple Reading.

A bistatic RFID interrogator, or reader, uses one antenna to transmit RF energy to the RFID tag and a different antenna to receive energy reflected back from the tag.

The region of the electromagnetic field, determined by the reader/interrogator antenna, in which the transponders are signaled to deliver a response.

A code added to the contents of a block of data stored on an RFID microchip 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.

A UHF reader antenna that emits radio waves in a circular pattern. These antennas are used in situations where the orientation of the tag to the reader cannot be controlled. Since the waves are moving in a circular pattern, they have a better chance of hitting the antenna, but circular-polarized antennas have a shorter read range than linear-polarized antennas.

A term to denote an event in which two or more data communication sources compete for attention at the same time and cause a clash of data, inseparable without some means of anti-collision or contention management.

A means of avoiding collisions or clashes of data from different sources competing for attention at the same time.

The condition that exists between devices or systems that exhibit equivalent functionality, interface features and performance to allow one to be exchanged for another, without alteration, and achieve the same operational service. An alternative term for Interchangeability.

A means of connecting a number of data communication devices and concentrating packets of data at a local point before onward transmission on a single link to a central data processor or information management system. In contrast to multiplexors concentrators usually have a buffering capability to ‘queue’ inputs that would otherwise exceed transmission capacity.

Term denoting simultaneous transponder responses capable of causing potential confusion, and misreading, within a reader/interrogator system unequipped with anti-contention facilities.

A mode of reader/interrogator operation wherein the identification of a transponder is reported or communicated continuously while the transponder remains within the interrogation field. See also In-field Reporting.

In a radio frequency identification system, the rate at which data is communicated between transponder and the reader/interrogator, expressed in baud, bits.s-1 or bytes.s-1

The reduction in performance of transponders and readers/interrogators caused by the close proximity of metal influencing the resonance of an electronic tuned circuit.

Term which defines the direction of communications as being from reader/interrogator to transponder. Alternative term for Forward Link.

A channel capable of transmitting data in both directions at the same time. (Half duplex is a channel capable of transmitting data in both directions, but not simultaneously.)

The length of time the reader can be emitting energy. Regulations in the European Union say readers can be on only 10 percent of the time.

A computer for running middleware or applications that is close to the edge of the network, where the digital world meets the real world. Edge servers are put in warehouses, distribution centers and factories, as opposed to corporate headquarters.

Two components distinguishable, radiation efficiency and aperture efficiency. Radiation efficiency is expressed as the ratio of total power radiated by the antenna to total power accepted by the antenna from source – for the transmission mode. Aperture efficiency is expressed as the ratio of effective antenna area to the real area of the antenna.

A process of transferring modulated data or energy from one system component to another, reader to transponder for example, by means of an electromagnetic field.

A process of transferring modulated data or energy from one system component to another, reader to transponder for example, by means of an electromagnetic field.

The spatial and temporal manifestation of an electromagnetic source in which magnetic and electric components of intensity can be distinguished and plotted as contours, like contour lines on a map, the planes of the electric and magnetic contours being at right angles to one another. Where the source is varying in time so too the field components vary with time. Where the source launches an electromagnetic wave the field may be considered to be propagating.

A means of securing data, often applied to a plain or clear text, by converting it to a form that is unintelligible in the absence of an appropriate decryption key.

The electronic circuits used to drive an antenna. The combination of exciter and antenna is often referred to as the transmitter or scanner.

The result of a ‘foreign’ or non-assigned transponder entering the interrogation zone of a radio frequency identification system and affecting a response, erroneous or otherwise.

The zone surrounding a reader/interrogator in which the reader/interrogator is capable of communicating with a transponder.

Entry of data by an original equipment manufacturer (OEM) or user into a transponder by means of a proprietary programming system, usually undertaken before the device is attached to the item to be identified or accompanied. This facility is usually associated with Write Once Read Many (WORM) and read/write (RW) devices.

The intensity of a field measured in units appropriate to the field concerned. Electric field strengths are measured in volts per meter (V.m-1) and magnetic field strengths in amperes per meter (A.m-1).

Coded instructions that are stored permanently in read-only memory. When upgrading a reader to read a new protocol, the firmware usually has to be changed. Some newer readers can be upgraded remotely over a network.

Communications from reader/interrogator to transponder. Alternatively known as Downlink.

A mode of operation in which a reader/interrogator reports a transponder ID on entering the interrogation zone and then refrains from any further reports until a prescribed interval of time has elapsed.

The ability to read from and write to a transponder while it is attached to the object or item for which it is being used.

A process of transferring modulated data or energy from one system component to another, reader to transponder for example, by means of a varying magnetic field.

A device that produces a RF signal for the purpose of data communications. Examples. Include garage door openers, cordless phones, RFID transmitter and so on.

The region in which a transponder or group of transponders can be effectively read by an associated radio frequency identification reader/interrogator.

A fixed or mobile data capture and identification device using a radio frequency electromagnetic field to stimulate and effect a modulated data response from a transponder or group of transponders present in the interrogation zone. Often used as an alternative term to Reader.

An antenna that focuses the radio energy from the reader in one orientation or polarity. This increases the read distance possible and can provide greater penetration through dense materials. Tags designed to be used with a linear polarized reader antenna must be aligned with the reader antenna in order to be read. (See circular-polarized antenna.)

In the RFID world, this term is generally used to refer to software that resides on a server between readers and enterprise applications. The middleware is used to filter data and pass on only useful information to enterprise applications. Some middleware can also be used to manage readers on a network.

A condition that exists when the data retrieved by the reader/interrogator is different from the corresponding data within the transponder.

The process or capability of a radio frequency identification reader/interrogator to read a number of transponders present within the system’s interrogation zone at the same time. Alternative term for Batch Reading.

A mode of operation in which the identification of a transponder is reported as or once the transponder leaves the reader interrogation zone.

A device that accepts the outputs from a number of data communication interfaces for onward transmission into a communications network.

The ability to enter data and to change data stored in a transponder.

An automatic identification and data capture system comprised of one or more reader/interrogators and one or more transponders in which data transfer is achieved by means of suitably modulated inductive or radiating electromagnetic carriers.

The maximum distance between the antenna of a reader/interrogator and a transponder over which a programming function can be effectively performed. Usually shorter than the read range, but may be influenced by orientation and angle with respect to the antenna, and possibly by environmental conditions.

The maximum distance between the antenna of a reader/interrogator and a transponder over which the read function can be effectively performed. The distance will be influenced by orientation and angle with respect to the antenna, and possibly by environmental conditions.

The maximum rate at which data can be communicated between transponder and reader/interrogator, usually expressed in bits per second (bps or bits.s-1).

An electronic device for performing the process of retrieving data from a transponder and, as appropriate, the contention and error control management, and channel and source decoding required to recover and communicate the data entered at source. The device may also interface with an integral display and/or provide a parallel or serial communications interface to a host computer or industrial controller.

The combination of antenna, transmitter (or exciter), and receiver into a single unit is often referred to as a scanner. With the addition of electronics to perform the necessary decoding and management functions to deliver the source data, the unit becomes a reader.

Usually denotes unwanted electromagnetic harmonics. Type Approval testing includes measurement of harmonic emissions arising from the reader, to ensure they are within specified limits.

A TRANSmitter/reCEIVER device used to both receive and transmit data.

An electronic device for launching an electromagnetic wave or delivering an electromagnetic field for the purpose of transmitting or communicating energy or modulated data/information. Often considered separately from the antenna, as the means whereby the antenna is energized. In this respect it is also referred to as an exciter.

Term which defines the direction of communications as being from transponder to reader/interrogator.