NFC

NFC, or Near Field Communication, is a short-range wireless technology which enables the communication between devices over a short distance. It is also called "contactless" because there need not be a real contact between the communicating devices, though the distance between them should be very short (about 10cm).

The most common contactless protocols are the following:

ISO 14443 Type A
Mifare	Is based on ISO 14443 Type A but includes NXP proprietary encryption & authentication
ISO 14443 Type B	This protocol uses the same Block Transmission Protocol as Type A (ISO 14443-4) but the physical layer and initialization procedure (anticollision and selection) are different from Type A
ISO 14443 Type B’ or Innovatron	This protocol use the same physical layer as Type B but the layers above are proprietary
Felica from Sony (Proprietary) also called type C
ISO 15693	This protocol is used for RFID Tags

The above protocols share some common behaviour depending on the device role:

Contactless Reader/validator

When switched-on, the contactless reader generates a Radio Frequency (RF) field
It starts polling for a contactless device by sending requests (REQA,REQB,…) periodically
If a correct answer is received, it executes an anticollision loop in order to detect all devices in the field. Then it selects one of them and starts data communication

Contactless cards

The power is provided by the RF field
An RF antenna is connected to the card to retrieve this power

Contactless mobile phones

Specifications of the NFC Forum to address use cases related to a contactless mobile phone environment

Antenna in on the mobile connected to a NFC chip, this NFC chip forwards contactless data to the SIM card