NFC技術規范:The International Standard ISO/IEC 18092, Near Field Communication – Interface and Protocol (NFCIP-1), defines an interface and protocol for simple wireless interconnection of closely
coupled devices operating at 13.56 MHz.The NFC Data Exchange Format (NDEF) specification defines a message encapsulation format to exchange information, e.g. between an NFC Forum Device and another NFC Forum Device or an NFC Forum Tag. NDEF is a lightweight, binary message format that can be used to encapsulate one or more application-defined payloads of arbitrary type and size into a single message construct. Each payload is described by a type, a length, and an optional identifier.
Type identifiers may be URIs, MIME media types, or NFC-specific types. This latter format
permits compact identification of well-known types commonly used in NFC Forum applications, or self-allocation of a name space for organizations that wish to use it for their own NFC-specific purposes.The payload length is an unsigned integer indicating the number of octets in the payload. A
compact, short-record layout is provided for very small payloads.
The optional payload identifier enables association of multiple payloads and cross-referencing between them.NDEF payloads may include nested NDEF messages or chains of linked chunks of length unknown at the time the data is generated.NDEF is strictly a message format, which provides no concept of a connection or of a logical circuit, nor does it address head-of-line problems.