There are many different types of radio frequency identification technology. This article explains the difference between active and passive tags and between low-, high- and ultra-high frequency systems.

Here are a few companies that could prove attractive.

Using active RFID tags, the Indy Racing League not only times and scores 16 events, it also provides critical data to drivers and race crews, and helps engine, tire and chassis makers develop products.

Race officials use an active-tag system to drive real-time reports on racers’ performance.

Nokia, Philips, Sony to push consumer RFID; Matrics unveils read-write Class 0+ tag; U.S. to hold wireless sensor conference; First smart active labels hit the market; Alien invades China; HID introduces RFID-mag stripe access control unit.