ISO/IEC 21481:2021

Information technology - Telecommunications and information exchange between systems - Near field communication interface and protocol 2 (NFCIP-2)

This document specifies the communication mode selection and switching mechanism, designed not to disturb any ongoing communication at 13,56 MHz, for devices implementing ISO/IEC 18092, the ISO/IEC 14443 or ISO/IEC 15693 series. The communication modes are specified in the respective International Standards and are outside of the scope of this document.

Technologies de l’information — Télécommunications et échange d’information entre systèmes — Interface et protocole 2 en communication de champ proche (NFCIP-2)

General Information

• Status: Published
• Publication Date: 19-Apr-2021
• ICS: 35.100.20 - Data link layer
• Technical Committee: ISO/IEC JTC 1/SC 6 - Telecommunications and information exchange between systems
• Drafting Committee: ISO/IEC JTC 1/SC 6/WG 1 - Physical and data link layers
• Current Stage: 6060 - International Standard published
• Start Date: 20-Apr-2021
• Due Date: 23-Aug-2021
• Completion Date: 20-Apr-2021

Relations

• Revises: ISO/IEC 21481:2012 - Information technology - Telecommunications and information exchange between systems - Near Field Communication Interface and Protocol -2 (NFCIP-2)
• Effective Date: 02-Jun-2018

Overview

ISO/IEC 21481:2021 defines the Near Field Communication Interface and Protocol 2 (NFCIP-2), a critical international standard for telecommunications and information exchange between systems. This third edition standard focuses on specifying the communication mode selection and switching mechanism for NFC devices operating at the 13.56 MHz frequency band. The key feature of ISO/IEC 21481:2021 is its design to enable seamless mode switching without disrupting ongoing communications, thus enhancing interoperability among devices implementing the ISO/IEC 18092, ISO/IEC 14443, or ISO/IEC 15693 series standards.

NFCIP-2 serves as a foundation for stable NFC communications by managing how devices detect external radio frequency (RF) fields and select communication modes. It complements and interfaces with specialized standards for different NFC communication modes, including PCD (Proximity Coupling Device), PICC (Proximity Integrated Circuit Card), and VCD (Vicinity Coupling Device). By doing so, it facilitates smooth transitions and coexistence between these modes within NFC-enabled devices.

Key Topics

• Communication Mode Selection
  NFCIP-2 devices implement a mechanism to select one of four communication modes-NFC, PCD, PICC, or VCD-based on detected external RF fields. The standard ensures that the chosen mode aligns with specific mode requirements defined in other international standards, providing consistency and interoperability.

• External RF Field Detection
  A crucial part of the protocol is the detection of any external RF field operating at 13.56 MHz with an intensity above a defined threshold. This detection prevents collisions and disruptions by ensuring a device does not generate its own RF field when another device’s communication is ongoing.

• RF Field Generation Control
  The standard governs when an NFCIP-2 device may generate its RF field. Devices only activate their RF emission if no external RF field is detected, thereby minimizing interference and ensuring reliable data exchanges.

• Mode Switching Procedure
  The documented sequence enables devices to switch communication modes without interrupting current communications. This dynamic switching improves device flexibility and supports complex NFC use cases, including seamless transitions between contactless card emulation, peer-to-peer, and reader/writer modes.

• Compatibility and Harmonization
  ISO/IEC 21481:2021 is harmonized with relevant NFC Forum requirements and complements standards such as ISO/IEC 18092 (NFCIP-1), ISO/IEC 14443, and ISO/IEC 15693, ensuring wide usability and global interoperability of NFC solutions.

Applications

• Contactless Payment Systems
  Enables secure and efficient transitions between card emulation and reader modes, facilitating smooth payment transactions without communication disruptions.

• Access Control and Identification
  Supports devices switching between various NFC modes used in secure access cards and identification badges.

• Smartphones and Consumer Electronics
  Provides a robust protocol for smartphones and other consumer devices to interact with NFC tags, cards, and other NFC-enabled devices with multiple communication modes.

• IoT and Connected Devices
  NFCIP-2 empowers IoT devices with reliable short-range communication capabilities, enabling device pairing, data exchange, and control without interference.

• Public Transport and Ticketing
  Ensures resilient NFC communication for transit cards, enabling quick mode changes during use in busy environments.

Related Standards

• ISO/IEC 18092 (NFCIP-1)
  Specifies the interface and protocol for NFC peer-to-peer communication used within NFCIP-2 devices.

• ISO/IEC 14443 Series
  Defines proximity card standards and communication modes (PCD and PICC) that are integrated under NFCIP-2.

• ISO/IEC 15693 Series
  Covers vicinity cards and devices (VCD mode), whose communication protocols are supported through the NFCIP-2 standard.

• NFC Forum Device Requirements
  Provides practical requirements and use case examples that align closely with the NFCIP-2 mode selection mechanisms.

• ITU-R Radio Regulations
  Allocates and regulates the 13.56 MHz frequency band used for ISM applications, which is fundamental for NFC communication.

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By adhering to ISO/IEC 21481:2021, manufacturers and developers ensure their NFC-enabled systems achieve stable, interoperable, and efficient communication across multiple operating modes, supporting an expanding ecosystem of contactless technologies worldwide.

Standards Content (Sample)

INTERNATIONAL ISO/IEC
STANDARD 21481
Third edition
2021-04
Information technology —
Telecommunications and information
exchange between systems — Near
field communication interface and
protocol 2 (NFCIP-2)
Technologies de l’information — Télécommunications et échange
d’information entre systèmes — Interface et protocole 2 en
communication de champ proche (NFCIP-2)
Reference number
©
ISO/IEC 2021
© ISO/IEC 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO/IEC 2021 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 2
5 Conventions and notations . 2
6 NFCIP-2 device . 2
7 External RF field detection . 3
8 RF field generation . 3
9 Mode selection and switching . 3
Bibliography . 5
© ISO/IEC 2021 – All rights reserved iii

Foreword
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Commission) form the specialized system for worldwide standardization. National bodies that are
members of ISO or IEC participate in the development of International Standards through technical
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described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for
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_experts/ refdocs).
Attention is drawn to the possibility that some of the elements of this document may be the subject
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rights. Details of any patent rights identified during the development of the document will be in the
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For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html. In the IEC, see www .iec .ch/ understanding -standards.
This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 6, Telecommunications and information exchange between systems.
This third edition cancels and replaces the second edition (ISO/IEC 21481:2012), which has been
technically revised.
The main change compared to the previous edition is the improvement of the specification of the mode
selection and switching mechanism.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html and www .iec .ch/ national
-committees.
iv © ISO/IEC 2021 – All rights reserved

Introduction
In 2002, Ecma International formed Task Group 19 of Technical Committee 32 to specify near field
communication (NFC) signal interfaces and protocols. The NFC devices are wireless, closely-coupled
devices communicating at 13,56 MHz.
Although ISO/IEC 18092 (NFCIP-1), ISO/IEC 14443 and ISO/IEC 15693 all specify 13,56 MHz as their
working frequency, they specify distinct communication modes. These are defined as NFC, PCD, PICC
and VCD communication modes.
This document (NFCIP-2) specifies the mechanism to detect an external RF field and select one
communication mode out of those four possible communication modes. Furthermore, NFCIP-2 requires
that subsequent behaviour be as speci
...