NFC Forum Issues Specifications for Near Field Communications
June 25, 2009 // Published as a news service by IHS
The NFC Forum released two candidate specifications designed to help the integration, implementation and standards interpretation of near field communication (NFC) technology.
The NFC Digital Protocol specification addresses the digital protocol for NFC-enabled device communication and provides an implementation specification on top of the International Organization for Standardization (ISO)/International Electrotechnical Commission (IEC) 18092 and ISO/IEC 14443 standards.
It harmonizes the integrated technologies, specifies implementation options and limits the interpretation of the standards, showing developers how to use NFC, ISO/IEC 14443 and Japanese Industrial Standard (JIS) X6319-4 standards together to ensure interoperability between different NFC devices and between NFC devices and existing contactless infrastructure, according to the NFC Forum.
The NFC Digital Protocol specification defines a 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, which are used by NFC-enabled devices to exchange data and bind to the NFC Logical Link Control Protocol (LLCP).
The LLCP specification defines an Open Systems Interconnection (OSI) layer-2 protocol to support peer-to-peer communication between two NFC-enabled devices. This is important for any NFC applications that involve bidirectional communications, experts said.
The specification defines two service types - connectionless and connection-oriented - organized 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 (deferring these issues to applications and to the reliability guarantees offered by ISO/IEC 18092 and ISO/IEC 14443 MAC layers), according to the NFC Forum.
The connection-oriented service adds in-order, "reliable" delivery, flow-control and session-based service layer multiplexing, experts said.
LLCP is a compact protocol, based on the Institute of Electrical and Electronics Engineers (IEEE) 802.2, designed to support either small applications with limited data transport requirements such as minor file transfers, or network protocols such as OBject Exchange (OBEX) and TCP/IP, which provide a more "robust" service environment for applications, according to the NFC Forum.
The NFC LLCP is promoted as delivering a solid foundation for peer-to-peer applications, enhancing the basic functionality offered by ISO/IEC 18092 but without affecting the interoperability of legacy NFC applications or chipsets.
Both the Digital Protocol and LLCP specifications are candidates for final release pending feedback from NFC Forum members and other standards organizations.
The NFC Digital Protocol and the LLCP candidate specifications are available at http://www.nfc-forum.org/specs/.
Source: NFC Forum.