How NFC Works

NFC is a short-range high-frequency radio technology. The NFCIP-1 standard specifies that NFC has a communication distance of within 10 centimeters, a operating frequency of 13.56 MHz, and a transmission speed of 106 Kbit/s, 212 Kbit/s, or 424 Kbit/s. The NFCIP-1 standard specifies the transmission speed, encoding and decoding methods, modulation schemes, and frame format of the RF interface of NFC devices in detail. This standard also defines the transmission protocol of NFC, including startup protocol and data exchange methods.
NFC operation modes are divided into passive mode and active mode. In passive mode, the NFC initiating device (also referred to as the master device) requires a power supply device. The master device uses the energy of the power supply device to provide a radio frequency field and send data to the NFC target device (also referred to as the slave device). The transmission rate needs to be one of 106 kbps, 212 kbps, or 424 kbps. The slave device does not generate a radio frequency field, so it is possible to use the radio frequency field generated by the master device to convert it into electrical energy, supply power to the circuit of the slave device, receive the data sent by the master device, and use load modulation technology to transmit the slave device data back to the master device at the same speed. In this operating mode, the slave device does not generate RF fields, but passively receives the RF fields generated by the master device. Therefore, it is called passive mode. In this mode, the NFC master device can detect non-contact cards or NFC target devices and establish a connection with them.
In active mode, both the initiating device and the target device must actively generate a radio frequency field when sending data to the other party, so it is called active mode. Both require power supply devices to provide energy to generate the radio frequency field. This communication mode is the standard mode for peer-to-peer network communication, enabling very fast connection rates.