This slide illustrates the types of Passive RFID and their frequency protocols. All radio signals operate using assigned frequency bands. In the United States, these frequencies are assigned by the Federal Communications Commission (FCC); however, frequency is a global concern. The FCC allows systems to operate using 125 MHz, 13.56 MHz, 433 MHz, 902 - 928 MHz, and 2.45 GHz. Tags operating in the 865 - 928 MHz are known as Ultra High Frequency (UHF). Tags operating using 13.56 MHz are known as High Frequency. In Europe the UHF Frequency band is standardized at 865 - 868 MHz and in the US the frequency band is standardized at 902 - 928 MHz. Most supply chain applications focus on the UHF frequency band due to the longer read ranges and low cost of the tags. It is important to note that significant improvements have been made in UHF tag performance due to better integrated chips and improved antenna design over the past several years.