Radio Frequency Identification (RFID): Definitions

(some of the of terms used in RFID technology)

range
The distance at which successful RFID reading or writing can be accomplished.
read
1. 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.
2. The extraction, decoding, and presentation of data from a tag.
read range
1. The distance from which a reader can communicate with a tag.

Active tags have a longer read range than passive tags because they use 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.

2. The maximum rate at which data can be read from a tag expressed in bits per second.
read rate
1. Often used to describe the number of tags that 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.

2. The maximum rate at which data can be read from a tag.
reader
1. 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.

2. The reader communicates with the RFID tag via radio waves and passes the information in digital form to a computer system.
3. A device that extracts and separates the information from the tag.
reader field
The area of coverage.

Tags outside the reader field do not receive radio waves and can't be read.

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 for additional relevant information.

reader-writer
A device that can not only read information but also write new information to a tag.
read-only tags
1. Tags that contain data that cannot be changed unless the microchip is reprogrammed electronically.
2. Tags that can only be read because they were programmed at the factory.
read-write tag
1. 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. Read-write tags are more expensive than read-only tags.

2. A tag that is reprogrammable.

Information can be added or changed.

reprogrammability
The ability to read from and to write data to the tag while that same tag is attached to its object.
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.

savants
Middleware created by the Auto-ID Center to filter data from EPC readers and pass it on to enterprise systems.

It was envisioned that "Savants" would reside on servers across the EPC Network and pass data to one another and act as a kind of nervous system for the network.

The term is being phased out by EPC Global and many of the functions of Savants are being incorporated in commercial middleware products.

scanner
1. An electronic device that can send and receive radio waves.

When combined with a digital signal processor that turns the waves into bits of information, the scanner is called a "reader" or "interrogator".

2. The part of a reader that can send and receive radio waves. It is also called an "antenna".
semi-passive tag
Similar to active tags, but the battery is used to run the microchip's circuitry but not to broadcast a signal to the reader.

Some semi-passive tags sleep until they are woken up by a signal from the reader, which conserves battery life.

Semi-passive tags can cost a dollar or more. These tags are sometimes called battery-assisted tags.

List of Radio Frequency Identification or RFID articles.