| A |
|
| |
|
Active Tag / Transponder
|
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. Compare to "passive tag". |
Addressability
|
The ability to address bits, fields, pages, files or other areas of memory in a tag. |
Air Interface
|
The conductor-free medium, usually air, between a transponder and the reader/interrogator through which the linking of the transponder to the reader /interrogator is achieved by means of a signal of radio, microwave or inductive frequencies. (UPU) |
AIT
|
Automatic Identification Technology (AIT) is a generic name given to devices used to automate data capture in a variety of applications. |
Algorithm
|
A set of steps guaranteed to effect a desired result by virtue of mathematical proof. A set of steps without the proof is referred to as a procedure. |
Alignment
|
An indication of the orientation of the tag, relative to the reader antenna in terms of pitch, roll, and yaw. (This is sometimes referred to as the coupling). |
Alphanumeric
|
A character set that contains alphabetic characters (letters), numeric digits (numbers) and usually other characters such as punctuation marks. |
Amplitude Modulation
|
Data is contained in changes in amplitude of the signal. The binary form is known as ASK (Amplitude Shift Keying) because the signal has only two states. |
API (application program interface)
|
A set of formalized software calls and routines that can be referenced by an application program to access underlying network services. |
Antenna
|
A device for sending or receiving electromagnetic waves. |
Anti-collision
|
A technique used to prevent several tags/transponders in the field of a single reader, or readers with overlapping fields, from interfering with one another. Anti-collision algorithms typically work by ensuring that the tags/transponders or readers don't transmitt at the same time. |
Architecture
|
The parameters by which computer or communications systems are defined. |
ASCII
|
American Standard Code for Information Interchange: a computer code, as described in ISO standard 646, consisting of 128 alphanumeric and control characters, each encoded with 7 bits (an 8th bit may or may not be used to include a parity check). The ASCII character set is used for information exchange between data processing systems, communication systems, and associated equipment. |
Asynchronous
|
Data transmission that is not related to the timing, or a specific frequency, of a transmission facility; transmission characterized by individual characters, or bytes, encapsulated with start and stop bits. |
Attenuation
|
The deterioration of signal strength, measured in decibels; opposite of gain. |
| |
|
| B |
|
| |
|
Backscatter
|
A technique for retrieving information from a passive tag in which the narrow band energy from the interrogator is reflected back to the interrogator in varying degrees as the impedance of the transmitter is modulated. |
Bandwidth
|
The range of frequencies available for signaling; the difference between the highest and lowest frequencies of a band, expressed in hertz (Hz). |
Baudrate
|
The rate at which a data channel transfers bits of information. The rate is measured in Bits Per Second (BPS). (This is not an accurate measure of the amount of information that can be transferred in a given time, as the number of bits that are needed for each character and start and stop bits, can vary. A more accurate measure is the Data Transfer Rate.). |
Binary
|
Denoting a numbering system to base 2 in which numbers are expressed as combinations of the digits 0 and 1, with positional weighting based on powers of 2. In computing these can be represented electrically by 'off' and 'on' respectively, or in machine-readable symbols by narrow and wide elements or by the absence or presence of a bar module. |
Bit
|
Abbreviation for binary digit. (1) A single element (0 or 1 ) in a binary number. (2) A unit of information capacity in a binary storage device. |
Byte
|
A sequential series of bits comprising one character and handled as one unit. A byte is usually comprised of eight bits, and represents either one alphabetic or special character, two decimal digits, or eight binary bits. It is usually encoded in the ASCII format. |
| |
|
| C |
|
| |
|
Capture field/area/zone
|
The region of the electromagnetic field, generated by the antenna, in which tags will operate. See "polar/field diagram." |
Carrier
|
An analog signal of fixed amplitude and frequency that is combined with a data carrying signal to produce an output signal suitable for transmitting data. |
Carrier frequency
|
The main frequency of a transmitter which is then modulated to transmit information. See "modulation." |
| Chip |
See microchip |
Collision
|
In networking or communications, an attempt by two nodes to send a message at exactly the same moment on a channel. |
| Closed Loop System |
Systems in which data handling is under the control of the owner of the RFID system. |
Continuous reporting
|
A mode of reader operation, where an tag ID is reported (at set time intervals) continuously while that tag remains in the field of the reader. See "in-field reporting." |
Corruption
|
When systems have poor error checking protocols, there exists a possibility that data reported by the reader is not the data transmitted by the tag. This is defined as corrupted data. |
| |
|
| D |
|
| |
|
Data
|
A general term (plural) for the basic elements of information that can be processed or produced by a computer. |
Data acquisition
|
The process by which data are moved from the site of an event to an environment in which the data can be processed into meaningful information. |
Data rate
|
In an automatic identification system employing RF, the rate at which data is communicated between the identification tag and interrogator. Typical units are bits per-second or bytes-per-second. |
Data stream
|
The string of data resulting from the reading of a single machine-readable medium or a string of concatenated machine-readable media. |
| Decimal |
The number representation system with a radix of 10. |
| |
|
| E |
|
| |
|
Electromagnetic
Coupling
|
Systems which in use a magnetic field as a means of transferring data or power are said to use an electromagnetic coupling. |
Electromagnetic Interference (EMI)
|
A device's radiation leakage that couples onto a transmission medium, resulting (mainly) from the use of high-frequency wave energy and signal modulation; reduced by shielding; minimum acceptable levels are detailed by the FCC (in the U.S.), based on type of device and operating frequency. |
Encryption
|
(1) Procedure of scrambling data through a series of calculations starting with a secret key, that makes it indecipherable without the secret key. The receiver of such data must perform the same calculations from the same key to get the data back to its original form.(2) (RFID) A system that scrambles the data being sent over the RF (Radio Frequency) transmission to prevent unauthorized access to the data. |
| EPC |
Electronic Product Code |
| |
|
| F |
|
| |
|
Frequency
|
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). The spectrum can be divided into the following frequency bands: (30 Hz to 3 GHz - radio waves; 3 GHz to 300 GHz - microwaves; 300 GHz to 428 THz - infrared radiation; 428 THz to 750 THz - visible light; 750 THz to 30 PHz - ultraviolet radiation; 30 PHz to 30 EHz - x-rays, 30 EHz to 3000 EHz - gamma rays). The majority of tags operate in the radio wave frequencies and some at the lower end of the microwave frequencies. |
Frequency Modulation (FM)
|
Data is contained in changes of the frequency of the signal. In the binary form the data is contained in the changes between two frequencies of the signal and is known as FSK. |
Full Duplex (FDX)
|
A channel capable of transmitting data in both directions at the same time. |
| |
|
| G |
|
| |
|
GHz (gigahertz)
|
one billion (1,000,000,000) cycles per second, unit of frequency |
| |
|
| H |
|
| |
|
Half Duplex (HDX)
|
A channel capable of transmitting data in both directions, but not at the same time. |
Handshasking
|
A mechanism for the regulation of the flow of data between devices, for example, to re-vent a computer sending more data than a printer can handle at that moment. This regulation can be achieved by both hardware methods (for example, RTS/CTS) and software techniques (for example, Xon/Xoff). |
Hz (hertz)
|
The international unit of frequency, equal to one cycle per second. |
| |
|
| I |
|
| |
|
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. |
Interface
|
A physical or electrical interconnection between communicating devices. (see RS232, RS422 and RS485) |
Interference
|
Unwanted electromagnetic signals, causing disturbance in the performance and communication of the RFID system. |
| Interrogator |
An RFID reader |
| |
|
| K |
|
| |
|
kHz (Kilohertz)
|
Abbreviated to kHz. One thousand (1,000) cycles per second, unit of frequency. |
| |
|
| L |
|
| |
|
Label
|
A piece of paper, cloth, polymer, metal, or other material affixed to something and indicating its contents, destination, or other information. |
| |
|
| M |
|
| |
|
Memory
|
Storing data in electronic form. Existing as RAM, ROM and WORM. |
MHz (Megahertz)
|
One million (1,000,000) cycles per second, unit of frequency. |
Microchip
|
A microelectronic semiconductor device comprising many interconnected transistors and ither components. Also called a chip or an "integrated circuit". |
Modulation
|
Changing the frequency, phase or amplitude of wave to transit data. |
| |
|
| N |
|
| |
|
Noise
|
Unwanted ambient electrical signals found in the operating environment of RFID equipment. See "interference." |
| |
|
| O |
|
| |
|
| ONS |
Object Name Service |
Open Loop System
|
An application in which independent parties may freely participate and in which bilateral arrangements are not necessary. Compare to "closed application environment." |
Orientation
|
Positioning with respect to a specific direction or plane. See "ladder orientation," "picket fence orientation. " (2) (RFID) Alignment of the tag with respect to the scanner, measured in pitch, roll, and yaw. |
| |
|
| P |
|
| |
|
Parity
|
A technique used to detect data transmission errors by adding an extra bit to each character. This bit is set to 1 or 0 to make the total number of bits ODD or EVEN, depending on the type of parity in use. |
Passive Tags
|
An RF tag that does not contain any internal power source. It is powered by signals from an external source (usually the electromagnetic field generated by the reader antenna). Compare to "active tag." |
| Phase Modulation (PM) |
Data is contained in changes in the phase of the signal. The binary form is known as PSK. |
Power levels
|
Levels of power radiated from a scanner or tag, usually measured in volts/meter. |
Protocol
|
A set of rules governing the flow of information in a communications system. A formal set of rules governing the format, timing, sequencing, and error control of exchanged messages of a data network; may be oriented toward data transfer over an interface, between two logical units directly connected, or on an end-to-end basis between two users over a large and complex network. Simple protocols define only hardware configuration; more complex protocols define timings, data formats, error detection, and correction techniques. |
| |
|
| R |
|
| |
|
Radio Frequencies
|
Electromagnetic emissions having frequencies between 30 Hz and 3 GHz. |
Radio Frequency Identification (RFID)
|
An automatic identification system comprising one or more reader/interrogators and one or more transponders in which communication and data transfer is achieved by means of electromagnetic energy of inductive, radio or microwave frequency with a variety of modulation and encodation schemes. |
Read
|
The decoding, extraction and presentation of data from formatting, control and error management bits sent from a tag. |
Reader / Writer
|
An electronic device that can act as both reader and programmer for an RF tag at a distance from it, specifically, while the tag remains attached to the object it identifies. |
Reading Distance
|
The distance (or range of distances) from the exit window of a scanner at which the scanner can reliably read a symbol. The minimum reading distance is equal to the optical throw and the maximum reading distance is equal to the range of the scanner. See "depth of field", "optical throw", "range". |
| Read-only memory (ROM) |
A form of stroing information which can not be overwritten or changed. |
Read Rate
|
The maximum rate at which data can be transferred from a tag to a reader. It is usually expressed in bits or bytes per second (bps). |
Read / Write (R/W)
|
Denoting a tag that can be re-programmed by an external RF signal, whilst the tag itself remains attached to an object. For re-programming the tag may need to be traveling at a reduced speed, and closer to the write head, than for normal reading operation. (Sometimes referred to as 'In-use programmed' or 'programming on the fly'). |
RS232
|
A common physical interface standard specified by the EIA for the interconnection of devices. The standard allows for a single device to be connected (point-to-point) at baud rates up to 9600 bps, at distances up to 15 meters. More recent implementations of the standard may allow higher baud rates and greater distances. |
RS422
|
A balanced interface standard similar to RS232, but using differential voltages across twisted pair cables. More noise immune that RS232 and can be used to connect single or multiple devices to a master unit, at distances up to 3000 meters. |
RS485
|
An enhanced version of RS-422, which permits multiple devices (commonly 32) to be attached to a two-wire bus at distances of over a kilometer. |
| |
|
| S |
|
| |
|
Sensor
|
An external/internal device used to measure a desired external or internal event. |
Spread spectrum RF
|
A method of transmitting a signal by spreading the data over a wider bandwidth than is normally needed to transmit the information. Two methods of spreading the RF carrier are direct sequence and frequency hopping. Spread spectrum devices are limited to < 1 watt of power by the FCC. |
Spread Spectrum / Direct Sequence (DSSS)
|
The method in which the RF signals are spread by carrier modulation with pseudo-random numeric code. Normally phase modulation is used at a rate several times the data rate. |
Spread Spectrum / Frequency Hopping (FHSS)
|
The method in which the RF signals are rapidly stepped through a series of frequencies in a pseudo-random code sequence.
|
| |
|
| T |
|
| |
|
Tag/Transponder
|
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 is tag. |
Tag ID
|
Tag ID is generic reference to either a Manufacturer Tag ID or User Tag ID. |
Tag initiated communication
|
The capability of an active tag to transmit a signal to an Interrogator that will cause the Interrogator to recognize the tag and respond. |
Tag-to-tag communication
|
The capability of RF Tags to communicate with each other as well as with an Interrogator.
|
Two-way
|
The capability of components in an RF system to both transmit and receive information. |
| |
|
| U |
|
| |
|
| UCC |
The Uniform Code Council. |
| |
|
| W |
|
| |
|
Write
|
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 Once/Read Many (WORM)
|
Denoting an RF tag that can be part, or totally programmed once by the user and thereafter only read. |
Write protection
|
The capability provided in the tag design which permits all or part of the memory to be shielded from modification, superimposition, or erasure. |
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. |
With the approval of DOD/AIT.
