Glossary Of Rfid Terms -- P
Passive
When used to refer to an RFID transponder, the term "passive" means a transponder has no power source and cannot actively broadcast a signal. A passive tag harvests energy emitted by a reader antenna, uses it to run the circuitry on an RFID chip and then reflects back a signal to the reader. Because the signal to the reader is reflected by the passive tag, the signal is weak and the read range of passive tags is thus relatively short.
Passive tag
An RFID tag without its own power source and transmitter. 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, packaging and other features.
Patch antenna
A term used to describe a 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.
Permalock
In the EPC Gen 2 standard, the ability to permanently lock a memory block.
Persistent memory
Memory that is not erased when a tag no longer is being powered by the reader or a battery.
Personal Identity Verification Format
A format for improving the identification and authentication of federal employees and contractors for access to federal facilities and information systems.
Phantom read
When a reader reports the presence of a tag that doesn't exist. This phenomenon is also sometimes called a phantom transaction or false read.
Phase
A part of a complete cycle of a waveform as measured from a specified reference point.
Phase Jitter Modulation
A variant of phase-shift keying, created by Magellan Technology, which operates at 13.56 MHz and complies with the ISO/IEC 18000 3 Mode 2 standard. PJM technology enables a write data rate of up to 424 kilobits per second and a read data rate of 106 kbit/s. It is particularly suited to item-level tagging in the pharmaceutical industry.
Phase shift keying
A method of communicating data by shifting the waveform's period. Instead of being at the zero axis at a specific point in time, the wave might be shifted forward so that it is at its peak. The reader's digital signal processor might interpret the out of phase signal as a one or zero.
Physical Markup Language
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 "soft drinks" in inventory.
PML
See Physical Markup Language
PML Server
A server that responds to requests for Physical Markup Language (PML) files related to individual Electronic Product Codes. The manufacturer of the item will maintain the PML files and servers. The name PML server has been replaced by EPC Information Service.
Portal
An RFID interrogator gateway used in manufacturing settings. Forklifts or other methods are used to transport tagged items through a portal reader to collect RFID tag data.
Power level
The amount of RF energy radiated from a reader. The higher the power output, the longer the read range, but most governments regulate power levels to avoid interference with other devices.
Printer
An RFID printer, or printer/encoder, is a device that prints a label with an embedded RFID transponder and encodes information in the chip within the transponder.
Printer/encoder
See printer
Private key
A cryptographic key known only to the owner.
Programming a tag
Writing data to an RFID tag. When a serial number is first written to a tag, this is sometimes called "commissioning a tag."
Protocol
A set of rules that govern communications systems. (See Air-interface protocol.)
proximity card
A proximity card is a card with a passive RFID transponder that can be read when placed near an RFID reader. Proximity cards usually use the ISO 14443 passive HF RFID standard, which is designed to have a short read range, to ensure that the tag-to-reader communication cannot be intercepted by a third party.
Proximity sensor
A device that detects the presence of an object and signals another device. Proximity sensors are often used on manufacturing lines to alert robots or routing devices on a conveyor to the presence of an object. They can be used in RFID systems to turn on readers.
Public key
The publicly available and distributed key used in public key cryptography systems.
Public key cryptography
A generic term for all public key algorithms. PKC uses a pair of numeric "keys," one public and one private key. The public key is published and can be used by anyone to either encrypt a message for the owner of the corresponding private key or to verify a signature generated by the owner of the secret key.
Public key infrastructure
A system of storing and distributing public keys together with their current status.
Pulse interval encoding
A method of sending data to an RFID tag by emitting pulses of energy with varying intervals, in order to indicate the ones and zeroes of binary code stored on the tag.