Appendix A - Radio Frequency Identification Defined
Overview
Page A-2 MDE-3664B TRIND® Start-up, Service, and Parts Manual · June 2013
Passive RFID tags operate without a separate external power source and obtain operating
power generated from the reader. Passive tags are consequently much lighter than active tags,
less expensive, and offer a virtually unlimited operational lifetime. The trade off is that they
have shorter read ranges than active tags and require a higher-powered reader. Read-only tags
are typically passive and are programmed with a unique set of data (usually 32 to 128 bits) that
cannot be modified. Read-only tags most often operate as a license plate into a database, in the
same way as linear barcodes reference a database containing modifiable product-specific
information.
RFID systems are also distinguished by their frequency ranges. Low-frequency (30 kHz to
500 kHz) systems have short reading ranges and lower system costs. They are most commonly
used in security access, asset tracking, and animal identification applications. HF (850 MHz to
950 MHz and 2.4 GHz to 2.5 GHz) systems, offering long read ranges (greater than 90 feet)
and high reading speeds, are used for such applications as railroad car tracking and automated
toll collection. However, the higher performance of HF RFID systems incurs higher system
costs.
The significant advantage of all types of RFID systems is the noncontact, non-line-of-sight
nature of the technology. Tags can be read through a variety of substances such as snow, fog,
ice, paint, crusted grime, and other visually and environmentally challenging conditions,
where barcodes or other optically read technologies would be useless. RFID tags can also be
read in challenging circumstances at remarkable speeds, in most cases responding in less than
100 milliseconds. The read/write capability of an active RFID system is also a significant
advantage in interactive applications such as work-in-process or maintenance tracking.
Though it is a costlier technology (compared with barcode), RFID has become indispensable
for a wide range of automated data collection and identification applications that would not be
possible otherwise.