In order to be compatible with contactless smart cards, the NFC
standard specifies a flexible gateway system, which is divided into three working modes: point-to-point communication mode, reader mode and NFC card emulation mode.
1. Point-to-point mode, in which two NFC devices can exchange data. For example, multiple digital cameras and mobile phones with NFC
function can be wirelessly interconnected by using NFC technology to realize data exchange such as virtual business cards or digital photos.
2. Read/write mode, in which the NFC device is used as a contactless reader. For example, a mobile phone that supports NFC plays the role of a reader when interacting with a tag, and a mobile phone that has NFC enabled can read and write tags that support the NFC data format standard.
3. Simulate card mode, this mode is to simulate a device with NFC
function as a tag or a contactless card, for example, a mobile phone that supports NFC
can be read as an access control card, bank card, etc.