Wal-Mart made a passive tag answer a reader, so pallets scanned themselves.

For decades a barcode was the fastest way to identify a product, but it had to be seen and scanned one unit at a time, so warehouses and registers paid for a person to align each package. The MIT Auto-ID Center proposed a cheap, passive UHF radio tag that could be read in bulk from a distance.

In 2004 Wal-Mart switched on its RFID pilot across eight Dallas-area sites, seven supercenters and one distribution center, after telling its top hundred suppliers they had to tag cases and pallets by January 2005. The tags are chips with radio antennas that answer a reader up to fifteen feet away, and the whole initiative centered on the electronic product code from EPCglobal, born out of MIT's Auto-ID Center.

The EPC was meant to replace the barcode. Where a barcode said what was in a box, the EPC said which exact pallet it was and where, so readers at dock doors could confirm a shipment the moment it arrived and feed inventory counts into the back-end systems without a scan. Tag prices were already falling, from about 60 cents to roughly 20 cents a year, as the standard drove volume.