Glossary Of RfidTerms

Glossary Of Rfid Terms -- R

2020-04-10 11:56:53 M&W SmartCard 50

Radio Frequency Identification

Any method of identifying unique items using radio waves. Typically, a reader (also called an interrogator) communicates with a transponder, which holds digital information in a microchip. But there are chipless forms of RFID tags that use material to reflect back a portion of the radio waves beamed at them.


See random access memory

Random access memory

Memory used for temporary storage of data. Information stored in RAM is lost when power is removed.


The process of retrieving data stored on an RFID tag by sending radio waves to the tag and converting the waves the tag sends back into data.

Read accuracy

This term usually refers to percentage of tags read successfully. If there are 100 tags in the field and 95 are read, the read accuracy is 95 percent.

Read field

See reader field.

Read lock

Locking one or more of a Tag’s memory areas so that a subsequent reader is required to exchange appropriate security safeguards with the Tag before being able to read these memory areas.

Read range

The distance from which a reader can communicate with a tag. Active tags have a longer read range than passive tags because they use their own power source (usually a battery) to transmit signals to the reader. With passive tags, the read range is influenced by frequency, reader output power, antenna design, and method of powering up the tag. Low-frequency tags use inductive coupling, which requires the tag to be within a few feet of the reader.

Read rate

A term usually used to describe the number of tags that can be read within a given period or the number of times a single tag can be read within a given period. The read rate can also mean the maximum rate at which data can be read from a tag expressed in bits or bytes per second. (See Data transfer rate.)


A term used to describe RFID tags that contain data that cannot be changed unless the microchip is reprogrammed electronically.


A term used to describe an RFID tag that can store new information on its microchip. These tags are often used on reusable containers and other assets. When the contents of the container are changed, new information is written to the tag.


A device used to communicate with RFID tags. The reader has one or more antennas, which emit radio waves and receive signals back from the tag. The reader is also sometimes called an interrogator because it "interrogates" the tag.

Reader field

The area of coverage. Tags outside the reader field do not receive radio waves and can't be read. This is also sometimes referred to as the read field.

Reader module

The electronics of a reader, including a digital signal processor, on a circuit board. Modules can be put in an RFID label printer or other device, as opposed to a standalone reader.

Reader talks first

A means by which a passive UHF reader communicates with tags in its read field. The reader sends energy to the tags but the tags sit idle until the reader requests them to respond. The reader is able to find tags with specific serial numbers by asking all tags with a serial number that starts with either 1 or 0 to respond. If more than one responds, the reader might ask for all tags with a serial number that starts with 01 to respond, and then 010. This is called "walking" a binary tree, or "tree walking." (See singulation.)

Real-time locating system

A system of finding the position of assets, using active RFID tags. The tags broadcast a signal, which is received by three reader antennas. The time each signal is received is passed on to a software system that uses triangulation to calculate the location of the asset. RTLS is used to find containers in a distribution yard, and many automakers use it to track parts bins within a large factory.

Received signal strength indication (RSSI)

A measurement of the strength of a radio signal being received. In RFID, RSSI is used to determine a tag's distance, as the signal is stronger from a tag that is closer to the reader antenna.

Return on Investment

The ratio of money gained or lost on an investment relative to the amount invested. The amount gained or lost may be referred to as interest, profit/loss, gain/loss or net income/loss, while the money invested may be referred to as the asset, capital, principal or cost basis of the investment. ROI is sometimes also known as "rate of profit" or "rate of return."

Reverse channel

The path through which energy travels from the RFID tag to the interrogator, or reader. It is also sometimes called the back channel.


See radio frequency identification

RFID Journal

The leading independent publication focused on radio frequency identification and its many business applications.

RFID tag

A microchip attached to an antenna that is packaged in a way that it can be applied to an object. The tag picks up signals from and sends signals to a reader. The tag contains a unique serial number, but may have other information, such as a customers' account number. Tags come in many forms, such smart labels that can have a barcode printed on it, or the tag can simply be mounted inside a carton or embedded in plastic. RFID tags can be active, passive or semi-passive.


See real-time locating system


A two-way, active wireless protocol designed for harsh-environment, high-security asset-visibility applications. The primary purpose of most RuBee deployments is to identify objects (often weapons), in order to better manage those objects.


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