Electronic Product Code (EPC) RFID Technology
Designed to be stored on an RFID tag, the Electronic Product Code
(EPC) is a unique number that identifies a specific item in the supply
chain. The EPC can be associated with dynamic data such as the
origination point of an item or the date of its production. Much like
a Global Trade Item Number (GTIN) or Vehicle Identification Number
(VIN), the EPC is key to unlocking the power of the information
systems that are part of the EPCglobal Network™.
EPCglobal Inc™ has responsibility for oversight of the EPC and the standards, specifications, and guidelines for the Auto-ID infrastructure to support its use. EPCglobal is a not-for-profit joint venture between GS1 (formerly EAN International) and GS1 US (formerly the Uniform Code Council). GS1 is a leading global organization dedicated to the design and implementation of global standards and solutions to improve efficiency and visibility in supply and demand chains. GS1 US is a not-for-profit member organization of GS1 and is dedicated to the development and implementation of standards-based, global supply chain solutions. For more information about EPCglobal, visit www.epcglobalinc.org.
From a data perspective, the UPC is the foundation of the EPC.
EPCglobal has published definitions that outline the EPC structure and
its relationship to the UPC. The way the data structures exist should
allow for easy migration from the UPC into the EPC environment with a
one-to-one correlation. EPCglobal fosters technical standards
development through Action Groups, composed of end users and solution
providers working together to advance RFID technologies and ensure the
needs of the community are met. All standards, specifications, and
guidelines are continually being reviewed by these Action Groups and
it is a good idea to revisit the site regularly to see new
The EPCglobal Network is a framework that enables immediate, automatic identification and sharing of information on items in the supply chain. The network consists of the ID System (EPC tags and EPC readers), EPC Middleware, EPC Information Services (which enable trading partners to exchange information), and Discovery Services, which is a suite of services to enable users to find data related to a specific EPC.
Where do you see the EPCglobal Network going, and
will we truly have end-to-end visibility of our shipments to these
The stated intent for the EPCglobal Network is to facilitate
end-to-end visibility of goods and assets in an n-tier supply chain.
The system, if widely adopted, could eliminate human error from data
collection, reduce inventories, keep products in stock, reduce loss
and waste, and improve safety and security. Much of the framework and
many of the components to support this network have been developed,
and there are no technological barriers to creating end-to-end
With regard to Generation 1, there are Class 0 and Class 1
specifications for tags in the UHF band. Class 0 was originated as a
protocol by Matrics Technology Systems (acquired by Symbol
Technologies) and Class 1 was originated as a protocol by Alien
Technologies. Class 0 has been defined by EPCglobal as a read-only
device. Class 1 is defined in the EPCglobal specification as a tag
that is one-time programmable. In practice, the products that are
available from Alien Technologies are reprogrammable. And
Matrics/Symbol has released "Class 0+" products, which are
based on the same protocol as the Class 0 device, but are, in fact,
With regard to Generation 2, Class 1 (Class 0 was dropped) standards were ratified at the end of 2004 as a response to the limitations of the Generation 1 standards. Gen 2 provides expanded data functionality and better performance, is designed to support EPC codes up to 256 bits long, and has the provision for extra data to be carried in the tag based on a single RFID protocol. In addition, G2 tags should be comparable with regard to radio frequencies (from 860 MHz to 960 MHz) globally, allowing tags to work consistently in different countries under differing emissions standards. Tags must be able to understand three different approved modulation schemes as well as be able to transmit at several different speeds or data rates. In addition, Gen 2 includes a method to support "dense-interrogator channelized signaling" (also called "dense reader mode"), which attempts to reduce interference among readers to make it less likely that reader signals will impede tag signals. An in-depth analysis of the differences between Generation 1 and Generation 2 protocols is discussed in Zebra's white papers Managing the EPC Generation Gap and Gen 2 Implications for Smart Label Printing.
Gen 2 protocols offer significant performance enhancements over the
first generation of EPCglobal UHF protocols, including superior tag
throughput, improved accuracy, and compliance with global spectrum
regulations. In addition, many new vendors have committed to
supporting EPC Generation 2 and have brought new designs to market.
This allows users to find the best tags for their applications;
leverage standards-based interoperability among tags, interrogators,
printer/encoders, etc.; as well as gain from aggressive pricing
spawned by competition. If you are starting your RFID pilot now, it is
best to go to Gen 2 right from the start.
Does "dense reader mode" mean I
don't need to worry about how close readers are to other RFID
No. While the enhancements in Gen 2 represent a major leap forward
in RFID technology improvements, it does not mean that users can
bypass the learning curve associated with an RFID pilot. They will
still need to understand the physical requirements of laying out an
RFID environment to minimize RF interference from hardware and to
optimize read rates. Ideally, users should identify where RFID data is
generated, transmitted, and utilized, so business process and
operational improvements—such as better real-time visibility of
products and inventories in the supply chain—can be achieved. Issues
such as training personnel and establishing metrics and milestones to
determine progress will also need to be addressed. To be sure that you
are going to have as smooth and seamless an RFID implementation as
possible, it is still wise to turn to seasoned, trusted RFID
specialists who have a solid track record in the technology.
With the improved interoperability and
performance of Gen 2 tags, does it matter very much which hardware we
choose? Won't all products that meet the standards work with each
Not necessarily, and it is still a good idea to conduct due
diligence and proper research before investing in Gen 2 products. Gen
2 is a flexible standard that can be implemented many ways by
different vendors. With dozens of variations of Gen 2-compliant tags
and hundreds more likely on the horizon, chips may vary in memory
size, programming speed, and other characteristics. In addition,
different antenna designs can perform better or worse when distance or
orientation to interrogators is changed. Also consider that the amount
of power the printer/encoder requires to write data to the RFID chip
is a complex function of the inlay's chip type, antenna design, and
antenna size. Users may need to use different tag designs to provide
optimal read performance on a variety of items. Each set of tags may
require different encoding power levels, making it important for
printer/encoder settings to be changed easily without requiring
extensive IT support or reprogramming. It is very wise to thoroughly
test Gen 2 media to ensure tags selected truly support a given
application. Consult experienced solution providers, like Zebra, to
ensure the proper smart label media is compatible with your
printer/encoder and optimized for your application.
The arrival of Gen 2 does not signal the retirement or obsolescence
of other RFID protocols. Gen 1 tags will likely be used through 2007
until existing supplies are exhausted. And RFID technologies are very
likely to rapidly evolve into future generations in the coming years.
In addition, different protocol standards can be used for different
applications, just as numerous barcode symbologies are used today.
Organizations should build their RFID infrastructure with
multi-protocol printer/encoders and interrogators. Multi-protocol
equipment provides investment protection and simplifies upgrades
because it can simultaneously support different RFID standards and tag
With all the recent and ongoing changes in RFID,
how can I ensure that what I choose today will support my RFID
initiative in the coming years?
A flexible, configurable, and upgradeable RFID infrastructure is
required to support Gen 2 and beyond as well as allow users to reap
the business benefits of improved operations. Features like
multi-protocol support, software-defined radios, and adjustable power
settings provide long-term investment protection and lower the total
cost of ownership of your RFID infrastructure as it matures and
evolves. When evaluating RFID investments, determine if the
1) meet your current needs for protocols, options, and features;
2) include simultaneous support for multiple RFID protocols; and
3) offer a low-cost, clear, easy, and efficient upgrade path that can sustain operations with minimal disruption.