There is a common misconception about what the terms RFID and NFC mean. This misconception is widespread enough that it pops up in threads quite regularly so I am making this wiki page for people to link to when needed to “nip it in the bud”.
Short Version:
RFID is the general class of technologies used in most of the Dangerous Things implants (Excluding the xGLO and magnet implants like the xG3 and m31).
NFC (Near Field Communication) is a subset of RFID that uses the 13.56 MHz frequency.
We often refer to 13.56 MHz as HF (High Frequency) and 125 kHz as LF (Low Frequency).
Long Version:
Radio-frequency identification (RFID) is a class of communication technology that uses inductive coupling between two “antennas”.
The frequency bands used by RFID technology vary greatly, the main bands used in implants are:
The LF band technically ranges from 120-150 kHz.
LF tags that you will commonly come across are typically used to access buildings (EM, HID 1326 (ProxCard II), Indala, AWIA …) as well as for animal identification. Most LF tags will be listed as 125 kHz. 134.2 kHz is also commonly listed as the frequency for tags such as the xBT and most pet microchips (see info on ISO 11784 and ISO 11785)
The HF band is at 13.56 MHz.
HF tags are also used for building access often in hotels as well as payment cards and transit cards. Specifically smart cards (ISO/IEC 15693, ISO/IEC 14443 A, B), ISO-non-compliant memory cards (Mifare Classic, iCLASS, Legic, Felica …) and ISO-compatible microprocessor cards (Desfire EV1, Seos). Some HF tags can be read by phones with NFC capabilities to bring up web URLs, contact info, etc (see NDEF)
RFID tags come in 2 distinct types, Passive and Active:
Passive tags are powered by energy from the RFID reader’s interrogating radio waves, these are the sort of tags used in implants currently as the power source is external and needs no direct contact with the chip. This comes at the cost of range and obviously limits the amount of power available to the chip inside tag.
Active tags are powered by a battery and thus can be read at a greater range from the RFID reader; up to hundreds of meters. This power source requirement currently prevents these types of tags being used in implants due to size, lifespan and most importantly safety issues with implanting batteries.
There are other common bands of RFID that are not used commonly in implants:
The UHF band operates at 865-868 MHz in Europe and 902–928 MHz in North America. It is used for many things, the most familiar being asset/stock tracking tags such as the stickers you find in products at shops.
The 433 MHz frequency is also classified as UHF but is more associated with active tags.
The microwave bands are at 2450-5800 MHz (802.11 WLAN and Bluetooth standards) and 3.1-10 GHz (Ultra wide band) and require active tags.