Overview
1 Overview
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.
1.1 Objectives
The NFC Data Exchange Format (NDEF) specification is a common data format for NFC Forum
Devices and NFC Forum Tags.
The NFC Data Exchange Format specification defines the NDEF data structure format as well as
rules to construct a valid NDEF message as an ordered and unbroken collection of NDEF records.
Furthermore, it defines the mechanism for specifying the types of application data encapsulated in
NDEF records.
The NDEF specification defines only the data structure format to exchange application or service
specific data in an interoperable way, and it does not define any record types in detail—record
types are defined in separate specifications.
This NDEF specification assumes a reliable underlying protocol and therefore this specification
does not specify the data exchange between two NFC Forum Devices or the data exchange
between an NFC Forum Device and an NFC Forum Tag. Readers are encouraged to review the
NFCIP-1 transport protocol [ISO/IEC 18092].
An example of the use of NDEF is when two NFC Forum Devices are in proximity, an NDEF
message is exchanged over the NFC Forum LLCP protocol. When an NFC Forum Device is in
proximity of an NFC Forum Tag, an NDEF message is retrieved from the NFC Forum Tag by
means of the NFC Forum Tag protocols. The data format of the NDEF message is the same in
these two cases so that an NFC Forum Device may process the NDEF information independent of
the type of device or tag with which it is communicating.
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