The identification chain
An RFID implementation combines a radio subsystem with software that interprets the resulting observations. The transponder normally contains an integrated circuit and an antenna. A reader generates and receives the signals required by the selected protocol. Host software converts the reported data into application actions. NIST describes RFID systems in terms of radio, enterprise and interenterprise subsystems. NIST SP 800-98: Guidelines for Securing RFID Systems, 2007.
| Component | Engineering responsibility |
|---|---|
| IC | Identifier, memory, command processing and available security functions |
| Tag antenna and construction | Energy coupling, response characteristics and physical integration |
| Reader and reader antenna | Radio communication, protocol support and the intended interrogation zone |
| Middleware or application | Filtering, data interpretation, authorization and business events |
| Operational process | Issuing, exceptions, replacement, audit and maintenance |
Passive, active and battery assisted designs
Passive tags obtain operating energy from the reader field. Active designs use an internal power source for radio transmission. Battery assisted passive designs use a battery for parts of their circuitry while retaining a backscatter communication method. These categories should not be confused with memory capacity or the presence of authentication. NIST SP 800-98: Guidelines for Securing RFID Systems, 2007.
The Roxtron catalog primarily concerns credential and tag formats. A passive product does not independently report its location to a cloud service. Location or event information is obtained when infrastructure interrogates the tag and associates the observation with a known context.
A read is an observation
A reader can report the same identifier repeatedly while a tag remains in its interrogation zone. The application must decide whether these observations represent a single arrival, continued presence or another business event. Design the duplicate handling and timing rules before integrating the result with inventory, access or transaction software.
An access application also requires a distinction between identification and authorization. The radio subsystem may successfully obtain an identifier while the application correctly refuses access because the credential has expired or lacks permission. Test both accepted and rejected transactions during qualification.
Define interfaces before selecting hardware
Record the IC protocol, reader firmware, data format and host interface. Establish which system owns the identifier and which system assigns application permissions. Specify how the installation behaves during network interruption, how missed reads are resolved and how replacement credentials are issued.
A procurement specification should describe these interfaces alongside the physical tag. Selecting an enclosure and a nominal frequency leaves essential compatibility requirements unresolved.