What do Japanese school children, avis rental cars, luggage traveling through an airport, and a palate of Wal-Mart goods have in common? These seemingly disparate people, places, and things all have electronic radio-frequency identification tags to indicate who or what they are. Better known as RFID, this technology is an evolutionary update to the venerable bar code. It broadcasts information about an item continuously instead of waiting for it to be scanned manually.

At their simplest, these tags are basic one-way information devices. By combining a short-range radio with the bare minimum of electronics, RFID tags can do everything from identifying an item in a store for pricing and inventory purposes to spotting luggage on its way through an airport to recording the journey of a shipping container halfway around the world. No bigger than a fingernail, the most common RFID tags hold only rudimentary information, often just a model designation or a serial number.

When a nearby scanner’s transmission hits the chip, the tags electronics are activated and the chip broadcasts its data.” These tags are like the electronic toll readers that now are used on many of our expressways” explains Robert Turk, national director for supply chain at Siemens and the company’s point man on RFID technology. “The scanning is automatic, and it can handle several tags at once.