Conventional RFID devices operate on a single one of many possible frequencies and employ one of many different encoding schemes. For example, systems are currently available that operate at 125 kHz, 13.56 MHz, 915 MHz, and 2.4 GHz. The RFID tags that are attached to the items to be tracked operate at only a single frequency and, in addition, may use unique and incompatible encoding schemes to transmit data at that frequency.
Current RFID systems operate by coupling the antenna of transceivers or RFID readers to the antenna of one or more “tags” attached to the items that are to be tracked. Conventional RFID readers are designed to work only with the tags supplied by a particular supplier. Readers are not designed to universally read multiple types of RFID tags. This limitation of the current readers may be attributable to the hardware-based processing of the response signal and decoding of the tag information. Specific radio circuitry is used to sense the reflected information from the RFID tag, filter the information, and shape it before it is fed to the processor. Although this technique is rather straightforward, it lacks the flexibility to deal with tags of different types, e.g., tags based on different frequencies and/or encoding schemes.