What does the RFID tag on my car do when I travel multiple times through a toll booth?
The RFID transponder on our car (usually affixed to the windshield) contains a unique serial number. As you pass through a toll-collection point, the RFID reader installed there sends a signal that wakes up the transponder, which then emits radio waves coded to a specific serial number. I won’t get too technical, but changes in the radio waves can be read as either ones or zeros, and this binary data is converted into a unique serial number. If the toll is $1, for example, that amount is charged to the account associated with the serial number transmitted. Each time you drive past that toll-collection point, the same thing happens and your account is again charged.
—Mark Roberti, Founder and Editor, RFID Journal
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