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Fast & Accurate UHF RFID
Created at MIT by the Auto-ID Center in 1999, the goal was to use the technological advances we've made since the bar code was released in 1963 to create the next generation of article identification. With this in mind it should come as no surprise that EPC Gen 2 technology is able to scan between 100-1,000 tags per second! EPC Gen 2 is also unique in it's vast array of potential uses and features.
Besides have exponentially more ID numbers available than bar codes, EPC Gen 2 also allows each item to be identified individually. This means attributes such as colour, cut and any other feature can be accurately tracked in addition to it's "item". This has enabled more accurate inventory tracking, even made real-time inventory a possibility, allowing you to make smarter business decisions.
EPC, or Electronic Product Code, is the trade name associated with the ISO/IEC 18000-6C RFID standards. It is also the best known UHF (Ultra High Frequency) technology which is why it's sometimes referred to as UHF. UHF actually refers to any technology operating between 300MHz and 1GHz. Beyond this (2.4GHz or 5.8GHz) is Super High Frequency or SHF.
When most people think about RFID, this is the the technology they are picturing; the one that made a big splash when it was adopted by Walmart.
EPC stands for Electronic Product Code.
The GS1 organization responsible for unified global identification standards is replacing the older UPC (Universal Product Code) bar codes with EPC Gen 2. UPC first started in 1963 and has been pushed past it's limitations in terms of scale-ability and feature set. EPC standards expanded the unique identifiers beyond our current needs with careful through given to the future expansion and demands we are likely to place on it in the future.
EPCglobal is the trade organization leading development of global industry standards and adoption of EPC Gen 2 UHF RFID for today's information hungry trading networks. EPCglobal organizations are in every country that is working towards making EPC the end to end supply chain standard.
As with most technologies, the lengthy name Electronic Product Code Class 1 Generation 2, has been shortened into a number of abbreviations including Gen 2, EPC Gen 2, and EPC C1G2. It's also adopted the unofficial name of UHF RFID or Ultra High Frequency RFID as it's the best known of the UHF technologies.
EPC Gen 2 or EPCglobal Class 1 Generation 2 defines the physical and logical requirements for a passive back scatter system, where the Interrogator Talks First (ITF) between 860MHz - 960MHz depending on the country. The plain English version being that the reader sends out a signal that powers the tag, allowing it to reply. Prior EPC tag standards were known as Class 0 and Class 1 of which neither was widely deployed. EPC Class 1 Gen 2 represents a major step in standardization, performance and quality.
Due to the increased use of the 860-960MHz UHF range for other electronics, EPC uses FHSS (Frequency Hopping Spread Spectrum), a technique which rapidly switches the carrier among many frequency channels during the radio signal transmission, to get the best possible read from the tag. Using FHSS the reader can get several different reads from the tag and then compare the results to determine if the read was successful or not.
EPC takes full advantage of the higher UHF bandwidth by supporting the reading of multiple tags at once, something not possible in most other RFID technologies. The readers accomplish this by asking tags to randomly select 2 numbers, the reader then decreases the first number incrementally until all tags are read. The second number creates the priority sequence for tags which selected the same first number.
Anti-counterfeiting through encrypted verification of the tags 128-bit key. Authenticity guaranteed since the tag cannot be cloned.
Data Encryption through inclusion of AES-128 and Grain-128A into the EPC Gen 2 Version 2 specification. You in tag data is safe.
User Memory Files allow different access privileges to each folder. Each partner along the supply chain can now write their data to the tag and have it read-only to everyone else.
Tag Hiding allows "privileged" readers to render tags "untraceable" and hide the tags memory. This would ensure only your readers can find you're tag, otherwise they remain completely silent.
EPC RFID can be used across a wide variety of applications. Ranging from retail inventory management, pharmaceutical anti-counterfeiting, vehicle fuelling, and parking lot entry. You can view some of the possibilities on our RFID Solutions page.
The EPC standard requires that the system operates from 860 MHz - 960 MHz frequency range. However there are a number of Organizations and Governing bodies that regulate the frequency and transmission power in the different countries. As such no country can legally operate over the entire band and have usually assigned a sub-set of this band for use in their country.
The two most common frequencies of operation are 860 MHz - 868 MHz which is recognized through most of Europe. The other common band range is 902 MHz - 928 MHz which is used in North America and various other countries. However some countries have adopted other frequency ranges or changed their regulations. Japan has recently finish a transition period to move their EPC frequency range from 952 - 956.4 MHz and 952 - 957.6 MHz to 916.7 - 920.9 MHz. You can view the GS1 global list of country regulations to ensure you comply with local laws.
The legal implications of operating an RFID system outside legal frequency ranges or transmission power is why it's important that you select knowledgeable RFID hardware providers who can tune the hardware to your regional requirements.
EPC Gen 2 Certified readers use the same O/S (operating system), low level reader command set (LLRP), and are totally interchangeable with other manufacturers without any changes. Simple swap in and swap out. The differences between manufacturers relate to functionality beyond the Gen 2 standard such as enhanced read and write sensitivities or tag direction sensing.
Gen 2 readers are capable of reading all Gen 2 tags, but are not interchangeable between manufacturers and may not even be interchangeable between models by the same manufacturer. Typically they have performance that's 30% to 50% less than a Gen 2 Certified reader, and prices that reflect this.
EPC tag capabilities are broken down into classes and each class has specific capabilities and is backward compatible to the preceding class. Each higher class maintains the previous capabilities and characteristics and adds new capabilities.
EPC Class 0 is Generation 1 also called Gen 1. Generation 1 are tags that you can write once and read many times (WORM). This class of tag is factory programmable and not field programmable.
EPC Class 1 is Generation 1 and Generation 2, also called Gen 1 and Gen 2. Class 1 tags are WORM tags but can be read by readers from other companies. EPC Class 1 Generation 2 (EPC Gen 2 or just Gen 2) are WMRM (Write Many Read Many) tags that have a minimum memory of 256 bits of which 96 bits is for the EPC number. Gen 2 tags have better tag identification, which allows the reader to eliminate duplicate reads during multiple tag scans. Gen 2 tags can also be read by all Gen 2 readers due to vendor neutral design specifications. Gen 2 tags read up to 10 times faster than Gen 1 and provide extremely high read rates on tags - literally 100%. In addition the actual I/C (Integrated Circuit - that can contain over 50,000 transistors) is 2 to 3 times smaller than the earlier Gen 1!
EPC Class 1 tags also have a function that can render the tag permanently non-responsive. Options to Class 1 tags are decommissioning and recommissioning of the tag, passwords protected access control and optional user memory.
EPC Gen 2 tags come in several different flavours - EPCglobal - meaning that the tag can be read at any frequency between 860 MHz and 960 MHz, EPC Gen 2 860 MHz. ~ 868 MHz, also known as European Gen 2 and Gen 2 902 MHz ~ 928 MHz known as the North American Gen 2. An excellent flavour of the EPCglobal tag is an EPC World Tag - this world tag has a maximum read deviation of 1.5 dBi over the entire read spectrum from 860 ~ 960 MHz making it perfect for world/global solutions.
Effectively you can use a single tag throughout the world that positively identifies the tagged item directly back to the source, hence end to end supply chain management and visibility.
Gen 2 tags come in a very wide variety of types, shapes and sizes that are usually designed for a specific application.
Generic longevity specifications for Gen 2 IC's are 40 - 50 year data retention and 100,000 write cycles
A pallet tag can have a read distance of over 10 meters when attached to the cardboard or wooden case, but when attached to a metal shelving support the pallet tag has a read distance of zero to 0.5 meters.
For attaching to metal objects a metal mount tag should be used and depending on the type of metal and the type of metal mount tag you can achieve a read range of 10 meters or more when attached to metal. Each metal object does provide a different metal mount tag requirement and depending on the overall environment the reader frequency may need to be changed in order to achieve the best read rate and distance.
Tags can also be orientation sensitive due to the inlays used in making the final tag. Some tags can only be read in a vertical or horizontal position, some tags will only read on the edge, and then some tags can be read regardless of the orientation. Just because your friend uses XYZ tag does not mean that this is the best tag for your application.
Each application needs to consider the read and write requirements and then look at the tag that meets those requirements. Temperature, read distance, working environment, storage environment, read angles, and more need consideration so you can then determine what Tag IC and antenna combination will work the best.
Using the right tag for your application can make the difference between a successful implementation or a failure!
All Gen 2 tags contain the same basic memory features:
96 bit EPC number support (can and is used for many other purposes as has read write capabilities)
32 - 64 bit tag identifier (TID) - identifies the manufacturer of the tag and also has read write capabilities
32 bit kill password to permanently disable the tag
32 bit access password to lock the read write characteristics of the tag and also set the tag for disabling
Some tags include user memory of up to 2048 bits or more depending on the tag.
EPC Class 2 tags are enhanced Gen 2 Class 1 tags. They contain all of the Class 1 features plus an extended TAG ID (TID), extended user memory, authenticated access control and additional features that will be defined in the Class 2 specification not yet completed.
EPC Class 3 tags have not yet been fully defined, but are battery-assisted passive tags (BAP) sometimes called semi-passive tags in UHF Gen 2. Anticipated features are a power source to supply power to the tag and/or its sensors and or sensors with optional data logging capabilities.
These new Class 3 tags will still communicate passively, meaning they will require a reader/interrogator to initiate communications and send information to the reader using either back scatter or load -modulation techniques (For a better understanding of RFID communications we recommend you take our 6 free lesson RFID course)
EPC Class 4 is active tag technology. The UHF tag will contain a battery and can initiate communications with a reader or with another tag. Class 4 active tags will not interfere with the communications protocols of Class 1, 2 or 3 tags. Class 4 tags with contain an EPC identifier, and extended Tag ID, authenticated access control, a power source, communications via autonomous transmitter, have optional user memory and optional sensors with or without data logging capabilities. This Class 4 tag is still in the early definition stage.