NFC Forum publishes candidate specs for device interoperability and peer-to-peer communication

The NFC Digital Protocol and the Logical Link Control Protocol candidate specifications are now available to download from the NFC Forum website.

CANDIDATE SPECS: The NFC Forum is seeking feedback on the NFC Digital Protocol and the NFC Logical Link Control Protocol before they are officially approved
CANDIDATE SPECS: The NFC Forum is seeking feedback on the NFC Digital Protocol and the NFC Logical Link Control Protocol before they are officially approved

The NFC Forum has released two new candidate specifications, aimed at fostering device interoperability and peer-to-peer device communication.

The NFC Digital Protocol specification is designed to help developers use NFC, ISO/IEC 14443 and JIS X6319-4 standards together to ensure global interoperability between different NFC devices and between NFC devices and existing contactless infrastructures. It provides an implementation specification on top of the ISO/IEC 18092 and ISO/IEC 14443 standards and defines the common feature set that can be used consistently and without further modification for major NFC applications in areas such as financial services and public transport.

The specification covers the digital interface and the half-duplex transmission protocol of the NFC-enabled device in its four roles as Initiator, Target, Reader/Writer and Card Emulator. The specification includes bit level coding, bit rates, frame formats, protocols and command sets used by NFC-enabled devices to exchange data and bind to the new LLCP protocol.

LLCP, the NFC Logical Link Control Protocol, is designed to support peer-to-peer communication between two NFC-enabled devices. A compact protocol, LLCP is based on the industry standard IEEE 802.2 and is designed to support either small applications with limited data transport requirements, such as minor file transfers, or network protocols, such as OBEX and TCP/IP, which in turn provide a more robust service environment for applications.

The specification defines two service types, connectionless and connection-oriented, organised into three link service classes: Connectionless service only; connection-oriented service only; and both connectionless and connection-oriented service.

The connectionless service offers minimal setup with no reliability or flow-control guarantees, instead deferring these issues to applications and to the reliability guarantees offered by the ISO/IEC 18092 and ISO/IEC 14443 MAC layers. The connection-oriented service adds in-order, reliable delivery, flow-control, and session-based service layer multiplexing.

“The NFC LLCP thus delivers a solid foundation for peer-to-peer applications, enhancing the basic functionality offered by ISO/IEC 18092, but without impacting the interoperability of legacy NFC applications or chipsets,” says the NFC Forum.

“As more NFC devices and applications come to market, it is essential that we ensure their smooth interoperability with earlier NFC implementations and existing contactless infrastructure such as ISO/IEC 14443 and FeliCa,” said Koichi Tagawa, chairman of the NFC Forum. “These two specifications are significant because they establish clear and well-defined parameters for the implementation behaviour of NFC devices and applications, thereby providing this needed assurance.”

Both the Digital Protocol and LLCP specifications are candidates for final release pending feedback from NFC Forum members and other standards organisations. “By releasing these specifications in advance, the NFC Forum is enabling organisations in the NFC ecosystem to begin integrating them into their own work,” the Forum explains. “This gives both NFC Forum members and other standards organisations an opportunity to both accelerate their development and provide valuable feedback that can be incorporated into the final specifications. Once the feedback has been evaluated and integrated, both specifications will be officially approved and released by the NFC Forum.”

Readers can download the candidate specifications free of charge from the NFC Forum website.

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