The EPC Class Structure

Toronto, ON, July, 2006 - The EPC Tag Class Structure is often misunderstood. 'Class' is not the same as 'Generation'. Class describes a tags basic functionality for example whether it has memory or a battery. Generation refers to a tag specification's major release or ver-sion number. The full name for what is popularly called EPC Generation 2 is actually EPC Class 1 Generation 2, indicating that the specification refers to the second major release of a specification for a tag with write-once memory.

The full EPC Class Structure is:

Figure: EPC Class Structure

The Class 0 designation was added to the Generation 1 system long after the Class 1 specification was created, as part of the process described in 1.i above. Class 1 tags, of which 'Generation 2' is an example, contain a write once memory for storing an Electronic Product Code. Class 2 tags add additional memory that can be changed fre-quently, for storing additional data ?for example from an onboard sensor. Class 3 tags add batteries for longer read ranges and higher reliability, but are fundamentally passive backscatter tags. Class 4 tags are essentially active tags that can communicate with other Class 4 tags as well as readers. Class 5 tags are not really tags at all - they are essentially wireless networked readers.

High volume, general availability of Generation 2 tags is expected some time in this moment. However, Generation 1 tags will not disappear from the sup-ply chain: instead Generations 1 and 2 will coexist for 6 to12 months while the Generation 2 learning curve ramps up. Depending on Generation 2 price and perfor-mance, and market conditions, this 'Generation 1 Shadow' could last until early 2007, when Generation 1 tags finally disappear from the supply chain. Tag technology will continue to evolve; around the time Generation 2 becomes established around 2006/7, end users and technology vendors expect work to begin on developing a 'Generation 3' system with further improvements to Generation 2 technology.