Freight Transportation Vulnerability, Security, and Productivity through RFID Cargo Seals ...

RFID Cargo Seals Role in Freight Transportation Vulnerability, Security, and Productivity

From Electronic Cargo Seals: Context, Technologies, And Marketplace ...

... "RFID Seals: RFID technologies are most common among electronic seals. Fundamentally, they marry RFID transponders or their components with manual seal components. There are two main types of RFID tags and seals, passive and active. Passive seals do not initiate transmissions--they respond when activated by the energy in the signal from a reader. Interrogated by a reader, a passive seal can identify itself by reporting its 'license plate' number, analogous to a standard bar code. The tag can also perform processes, such as testing the integrity of a seal. The beauty of a battery-free passive seal is that it can be a simple, inexpensive, and disposable device. Although not a formal term, it is useful to think of such devices as 'pure passive'--a term that describes what most practitioners have in mind when they discuss passive RFID electronic seals. Passive RFID seals can carry batteries for either or both of two purposes. The first is to aid communication by boosting the strength of the reflective signal back to the reader. This capability need not add much cost. The second purpose is to provide power so functions can be performed out of the range of readers. One example of the latter is to power a clock, continuously test the integrity of the seal, and record the time of tampering. Adding substantial capability could raise the cost of a passive seal sufficiently that it would be practical only as a reusable product. Practitioners use three different terms to describe passive tags with batteries. They are semi-active, semi-passive, and battery-assisted passive. Since the terms seem to be interchangeable, this is a source of confusion in RFID tag discussions. Alien Technologies began using the term semi-passive and is now transitioning to the term battery" ...