TECHNOLOGY  

    The technology commonly associated with and collectively called “RFID” extends beyond the RFID tag on a product.  RFID system technology can be categorized into the physical technology (RFID tag and RFID tag readers) and information technology (Electronic Product Code (EPC), middleware, Object Name Service (ONS) and Physical Markup Language (PML)).   Over the past two years, improvements in RFID physical technologies and near worldwide adoption of RFID information technology standards have resulted in enormous improvements to RFID system reliability and accuracy.    

RFID TAGS

     An RFID tag is an electrical device placed onto a product, be it at the pallet, case or individual item level.  An RFID tag is composed of a computer chip, an antenna integral to the tag, a battery in active tags, and packaging to encase the components.  The computer chip can store up to 128 Kbytes of information and is essentially the same as other computer chips in use. 

     The computer chip contains the Electronic Product Code for the product, and based on application and tag capabilities, can store other information such as environmental conditions experienced by the product or if GPS equipped, the products location. 

     Passive tags utilize the RF energy of the RFID reader (via induction) to power the tag.  The effective range of passive tags is approximately 5 to 15 feet, and the tag is read only. 

    Active and semi-active tags contain batteries and transmit using power from the battery or a combination of the RFID reader RF energy and the battery to power the tag.  Active tags have much greater range (as far as hundreds of feet depending on size and transmission frequency), and have read/write capabilities.  RFID tags operate across the frequency spectrum, from low frequency (30 to 500 KHz), thru ultra high frequency (800 to 900 MHz) to microwave frequencies (1 to 2 GHz). ¹

RFID READER

     The RFID reader is a scanning device that is capable of reliably reading and communicating with RFID tags beyond line-of-sight, and the RFID middleware.  The RFID reader uses its own antenna to communicate with the tag by transmitting RF energy at a designated frequency associated with the tag, causing the tag to respond with EPC data embedded in the tag’s computer chip.  Readers can communicate and process information from multiple tags nearly simultaneously, with current read rates of approximately 100 tags per seconds, with estimated reliable read rate of over 1000 tags per second within the next year.  Readers can be mobile, hand held, or stationary such at point of sale readers and large entranceway portal readers. ¹    

ELECTRONIC PRODUCT CODE (EPC)

     The EPC is a unique number that identifies a specific item in the supply chain and is stored on the RFID tag.  The standardization of EPC Class 1 Generation 2 codes (Gen2) in December 2004 by EPCglobal ³ set the standard for EPC codes for worldwide adoption.  Most EPC Gen2 codes are 96-bit and are broken down into four groupings: (1) “Version” or “Header” consisting of 8-bits and is designated by EPCglobal and identifies the length, types, structure and generation of the EPC, (2) “Domain Manager,” consisting of 28-bits, is specified by EPCglobal and identifies the manufacture, (3) “Object Class,” consisting of 24-bits, is assigned by the manufacture, and (4) “Serial Number,” consisting of 36-bits, is assigned by the manufacture and used to identify the specific product (be it at the pallet, case or individual item level).  Worldwide acceptance of EPCglobal is a significant milestone for RFID systems and will allow those firms complying with the standard to utilize RFID generated data throughout their supply chain. ²       

MIDDLEWARE

     Middleware, also known as RFID manager software, integrates the various data transmitted by RFID tags being processed by one or more RFID readers, making the data useable by other supply chain management software.  The middleware processes as close to the source as possible, filtering out non-essential and multiple receipt of the same RFID tag information.  The middleware further formats the RFID data for transmission via intranet or the Internet.  Additionally, middleware also includes tools to monitor and control RFID readers and other functions of the local RFID system. 1, 3  

OBJECT NAME SERVICE (ONS)

     The ONS provides a global lookup “service” to translate EPCs into common Internet Uniform Reference Locators (URLs) where more detailed information on the item tagged is retained.  These EPC URLs can identify an EPC Information Service, an EPC website or other Internet resource containing information on the product.  ONS was developed as an “open architecture” (similar to the Internet) and allows EPC data to be quickly and efficiently transmitted over the Internet.  ONS allows EPC tagged products to be linked in real time to existing information or record real-time obtained information of the product as it moves through the supply chain. ²         

PHYSICAL MARKUP LANGUAGE (PML)

      “PML is a collection of common, standardized XML vocabularies to represent and distribute information related to EPC Network enabled objects.”  PML is EPCglobal and the RFID industries’ attempt to standardize interfaces and protocols for the communication with and within EPC Information Service of physical information concerning the product tagged.  Examples of PML data would be the location the where an EPC was read, the products weight, dimensions, and other physical and environmental condition data known about the product. ^{2, 4}