Technical standards set by EPCglobal enable RFID tags to be grouped according to minimum capabilities. Each class adds to features of the basic class 1 tag, which is “passive”: it depends on a reader to initiate communi­­­­­­­­­­­­cation and supply power. Passive tags can be read from as far away as 30 feet, active tags from 300 feet or more.

  Minimum Function Some uses
Class I (Passive)
  • Unique identifier number
  • "Kill function" to disable tag
  • Memory programmable only once
  • Newer "Gen 2" versions may be rewritable and password-protected
  • Parts and inventory
  • Enhanced U.S. driver's license
  • Key card
Class II (Passive)
  • Extended ID number
  • Additional memory, rewritable
  • Password access
  • E-passport
  • Credit card
  • National IDs
Class III (Semi-passive)
  • One or more sensors and a power source
  • Container and storage sensors
Class IV (Active)
  • Transmitter and power source
  • Can initiate communication with a reader or another tag
  • Car key fob
  • Animal tag
  • Toll pass