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Originally Posted by Clodfobble
I don't know about EZPass, but TXTag is definitely RFID.
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I don't think so. The ariticle says that TX Tag system will operate at 915 Mhz. Return to what an RFID chip does. First it generates electricity from the externally transmitted signal. Then it used that energy to transmit information inside the chip. It's life expectancy is virtually infinite.
From a Dec 2005 article in IEEE Spectrum:
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... August issue of Nature Materials ... they obtained 8-volt dc when the receiver coil of the RFID was placed in a 50-MHz electromagnetic field. The rectifier should work at frequencies up to 800 MHz.
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This chip used a relatively new material to obtain higher frequencies: pentacene. If TX is using 915 Mhz, then it is not RFID.
EZ Pass users have a transponder. A transceiver in a thin box also contains a lithium battery. Lithium life expectancy is 5 years. However at least one EZ Pass user had a battery fail after three years. She ignored repeated messages about EZ Pass not accepted. Then they started ticketing her. Only then did she get her EZ Pass replaced. If I remember, EZ Pass operates on 915 Mhz. Other systems such as in VA operate on a different frequency. However EZ Pass can be read in VA (and maybe farther south to SC) because toll booths also contain additional hardware for reading EZ Pass transmitters.
EZ Pass, et al are active devices. They transmit when a message is received requesting that transmission. If its battery goes dead, then no response. RFID uses no battery. RFID is powered by RF fields; not by a battery. In that 2005 article, best frequency was 800 Mhz - and it was probably weak at that frequency. RFIDs typically operate below 100 Mhz.
As for cancer myths - even cell phone operate at higher frequencies and with significantly more power.