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