Two health-care companies and two Department of Defense agencies are testing a prototype of a new active RFID system known as Roll-Call. The new system promises tags that are smaller and less expensive than active tags currently on the market, and that are designed to operate in hostile environments, such as those with densely packed, tagged products or a high quantity of metal. The Roll-Call system can not only determine a tag's location but reportedly can provide information regarding the tag's movement and any activity around it.
Unlike most RFID transponders, whether passive or active, a Roll-Call tag transmits only its license plate (the payload) at a preprogrammed rate-every five seconds, for example-while it has no other built-in intelligence or "overhead," such as instructions allowing the tag to store information or receive transmission from readers. The tag, described as "brain dead," simply transmits a ultrahigh-frequency 900 MHz signal encoded with an ID number, using a proprietary air-interface protocol. Because that is all the data being sent, it can operate in environments in which passive or other active tags may struggle, such as around large amounts of metal.
