Radio Frequency Identification (RFID): Definitions

(some of the of terms used in RFID technology)

object name service, ONS
An Auto-ID Center-designed system for looking up unique Electronic Product Codes and pointing computers to information about the item associated with the code.

ONS is similar to the Domain Name Service, which points computers to sites on the internet.

omni-directional
The capability of a tag to operate in any orientation.
one-time programmable tag
Also called a field-programmable tag.

An RFID tag that can be written to once and read many times (see WORM).

orientation
1. The position of a tag antenna vis-a-vis a reader antenna.

With UHF systems, readers can be either circular-polarized or linear-polarized. When using a linear polarized antenna, the tag reader and antenna reader must be in alignment in order to achieve the longest reading distance.

If that tag antenna is aligned vertically and the reader is sending out signals horizontally, only a small portion of the energy emitted by the reader will will hit the tag antenna.

2. Alignment of the tag with respect to the reader or tag.
passive tag
1. An RFID tag without a battery.

When radio waves from the reader reach the chip’s antenna, the energy is converted by the antenna into electricity that can power up the microchip in the tag.

The tag is able to send back information stored on the chip. Today, simple passive tags cost from U.S. 20 cents to several dollars, depending on the amount of memory on the tag and other features.

2. A tag that contains no internal power source.

It typically derives its power from the carrier signal radiated from the scanner or reader. This type of tag is used in all library RFID systems.

patch antenna
A small square reader antenna made from a solid piece of metal or foil.
penetration
The ability of a particular radio frequency to pass through non-metallic materials.

Low-frequency systems have better penetration than UHF systems.

phantom read
Also called a phantom transaction or false read.

This takes place when a reader reports the presence of a tag that doesn't exist.

physical markup language, PML
An Auto-ID Center-designed method of describing products in a way computers can understand.

PML is based on the widely accepted eXtensible Markup Language used to share data over the internet in a format all computers can use.

The idea is to create a computer language that companies can use to describe products so that computer can search for, say, all "softdrinks" in inventory.

PML Server
A server that responds to requests for Physical Markup Language (PML) files related to individual Electronic Product Codes.

The PML files and servers will be maintained by the manufacturer of the item. The name PML server has been replaced by EPC Information Service.

power level
The amount of RF energy radiated from a reader or an active tag.

The higher the power output, the longer the read range, but most governments regulate power levels to avoid interference with other devices.

programming a tag
1. Writing data to an RFID tag.

This is sometimes called "commissioning a tag".

2. Adding to or altering the information in a tag.
proximity sensor (s) (noun), proximity sensors (pl)
A device that detects the presence of an object and sends a signal to another device: Proximity sensors are often used on manufacturing lines to alert robots or routing devices on a conveyor belt to the presence of an object that is approaching.

radio frequency identification, RFID
1. A method of identifying unique items using radio waves.

Typically, a reader communicates with a tag, that holds digital information in a microchip; however, there are chipless forms of RFID tags that use material to reflect back a portion of the radio waves beamed at them.

2. A system that reads or writes data to RF tags that provide identification and other information pertaining to the object to which the tag is attached.

The tags have storage capacity for at least an identification number.

radio frequency, RF
A system that communicates over a radio link between a data source and a scanner or reader.

When used in the context of theft detection systems, it refers to a system that uses tags that can only be turned on and off.

List of Radio Frequency Identification or RFID articles.