Archive for September, 2009
RFID passive standards
by passive on Sep.08, 2009, under Overview, Passive RFID tags
There is no international body governing the use of RFID frequencies. Each country decides its own practices, usually the national communications authority. This introduces some restrictions on the use of RFID tags. For example, ultra high frequency tags cannot be used on a global basis without common standard. Frequencies licensed for RFID use in one country might conflict with ranges allocated to civilian or military use in another country.
Despite this, a number of standards are in place dealing with specific aspects of RFID technology.
The International Standards Organisation (ISO) lists over 30 current standards covering areas such as reader protocols, performance test methods, guidelines for use in item management and in animals. Over 20 additional standards are currently at various pre-issue stages.
EPCglobal is a venture founded by the global standards organisations GS1 and its American member organisation, GS1 US, who are primarily involved in the development of standards for supply chain management, and previously set global standars for barcodes. EPCglobal’s brief is to provide similar standard for commercial applications of RFID technology, and works with both suppliers and end users to set standards benefitting both.
EPCglobal was responsible for developing the EPC Gen 2 standard in 2004, which provides a protocol for communication for UHF RFID tags operating in the 860-960MHz range. This standard was subsequently ratified by the ISO and incorporated into ISO 18000-6. This standard provides for uniquely numbered RFID passive tags acting as an Electronic Product Code (EPC), which can be read globally by any EPC-compliant RFID reader.
The benefits of a guaranteed unique EPC serial number are obvious – any such RFID passive tag can be tracked worldwide. The EPC also provides a specification for a network through which this tracking can be done – the RFID reader passes the information to a computer which queries a name service to determine where to access further details on the tagged object, in a similar fashion to how a DNS resolves a web address. Together with standards for how data is stored, read and updated, EPC Gen 2 provides a complete framework for international use of RFID passive tags for supply chain management.
The issue of available UHF frequencies in different coutries is still present, however. EPCglobal maintains a list of UHF RFID regulations in both GS1 member countries and major non-members, which includes permitted frequencies and power levels in each country.
EPCglobal also provides a set of recommendations on how RFID passive tag use should respect consumer privacy, making consumers aware of the presence of RFID passive tags on products, advising them on how to disable or remove them or learn more about them, and ensuring that personally identifying information is not retained.
Passive RFID tag cost factors
by passive on Sep.02, 2009, under Cost, Overview, Passive RFID tags
Active RFID tags generally cost at least double figures, although they provide greater range and typically more functionality than their passive counterparts. RFID passive tags cost far less, although price can vary depending on a range of factors.
The amount of memoryon the chip is a major factor, and different sizes are suitable for different applications. Lower cost tags might only offer 96 bits of storage. That’s 12 characters, assuming 8 bits per character. While this might be enough to hold a product key or a unique serial number, it will need an external database to hold further details, which your reader will need to be able to connect to. A tag with 512 bits providing 64 characters might negate the need for database connectivity, while larger chips storing 1-8 Kb could store both current and historical data directly on thechip without ever needing to refer to an external source.
High frequency tags can cost from twice to four times as much as ultra high frequency tags with the same characteristics.
The tag housing needs to be considered: tags embedded in fobs or cards will cost more than a simple tag mounted on a substrate. Another common tag format is smart labels: RFID passive transponders inserted between printed labels and an adhesive backing.
Tags which are shielded to function in harsher conditions, or to work near metal surfaces which would normally interfere with the signal, will be more expensive.
Increasing the range of the transponder will add to the expense, particularly as RFID passive tags have a much shorter range than active tags, due to their need to draw their power from the RFID reader.
Quantity, as always, can be a major factor. Bulk order of hundreds of thousands might save as much as 20% against order measured in the tens ofthousands.
These are some of the main factors influencing the cost of passive RFID tags. The other side of the RFID cost equation is the cost of RFID readers.
RFID passive tags help improve quality of international mail delivery
by passive on Sep.01, 2009, under Applications, News
The United Nations co-ordinates international mail through the Universal Postal Union. They have recently implemented a new Global Monitoring System (GMS), using passive RFID tags to track international deliveries of letter-post in order to monitor quality of service.
From August to December 2009, over twenty thousand letters containing passive RFID tags will be sent through 45 international postal facilities. The tags will identify the letters as they pass through post office exchanges throughout the world, and the tracking information will be used by the UPU to help improve efficiency and identify areas of concern.
In development over the past three years, the GMS has been made possible by the availability of low cost passive RFID tags. At an average of 30 US cents each, their affordability allows the extension of the monitoring system to a wide range of countries, both developing and industrialized. 21 countries are taking part in the first phase of the project.
Individual postal organisations will be able to use the GMS to assess their domestic service quality, improving which should also lead to an improvement in international mail performance.
From the start of 2010, an additional thirty countries are expected to join the project. It is hoped that up to 100 countries will be involved by 2012.
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