RFID systems have been created in several frequency ranges, such as 125 KHz, 134 KHz, 13.56 MHz, 958 MHz and 2.4 GHz. The most widely adopted frequency is 13.56 MHz. 

The International Standards Organization has published standards for interoperability of 13.56 MHz RFID systems. The two primary standards are ISO 15693 and ISO 14443. ISO 14443 is primarily concerned with contactless smart card (financial transaction) applications. ISO 15693 is a more open standard, useful for a variety of AIDC applications. 

RFID has several advantages over other data collection technologies. Physical contact between the reader and the transponder is not necessary. In fact, line of sight is not even required. A tag may be attached to a package in the form of a smart label, worn on a person in the shape of a wristband, attached to a ring of keys or carried in a purse along with conventional credit cards. Examples of RFID in everyday use include "proximity" access control, vehicle immobilizer systems, animal identification, express package routing and fuel dispensing programs.