GS1's EPC "Gen2" air interface protocol, first published by EPCglobal in 2004, defines the physical and logical requirements for an RFID system of interrogators and passive tags, operating in the 860 MHz - 960 MHz UHF range. Over the past decade, EPC Gen2 has established itself as the standard for UHF implementations across multiple sectors, and is at the heart of more and more RFID implementations.
2008 saw the publication of Gen 2 Version 1.2.0 which incorporated a number of enhancements requested by the retail community to support their RFID rollouts at item level.
The most recent update, Gen2v2, was developed in response to the requirements of the EPCglobal user community, and features a number of backwards-compatible, optional features.
GS1 maintains an overview of frequency allocations for use of RFID at UHF bands around the world, in order to help organisations understand the international regulatory landscape.