ISO/IEC 18000-63:2026

• Abstract:

  This document establishes the air interface for radio frequency identification (RFID) devices operating in the 860 MHz to 930 MHz industrial, scientific and medical (ISM) band used in item management applications. This document specifies a common technical specification for RFID devices that can be used to develop standards for applications using this radio identification (RAIN) air interface. This document is intended to improve compatibility and encourage inter-operability of products for the growing RFID market in the international marketplace. This document establishes the forward and return link parameters for technical attributes including, but not limited to, operating frequency, operating channel accuracy, occupied channel bandwidth, maximum effective isotropic radiated power (EIRP), spurious emissions, modulation, duty cycle, data coding, bit rate, bit rate accuracy, bit transmission order, and, where appropriate, operating channels, frequency hop rate, hop sequence, spreading sequence, and chip rate. This document further specifies the communications protocol used in the air interface. This document describes the physical and logical requirements for a passive backscatter, Interrogator-talks-first (ITF), radio frequency identification system operating in the 860 MHz to 930 MHz frequency range. This document specifies: physical interactions (the signalling layer of the communication link) between Interrogators and Tags; logical operating procedures and commands between Interrogators and Tags; the collision arbitration scheme used to identify a specific tag in a multiple-tag environment; optional security commands that allow the use of crypto suites of ISO/IEC 29167-1:2014.

• Status: Published
• Publication Date: 29-Oct-2026
• ICS: 35.040.50 - Automatic identification and data capture techniques
• Technical Committee: ISO/IEC JTC 1/SC 31 - Automatic identification and data capture techniques
• Drafting Committee: ISO/IEC JTC 1/SC 31 - Automatic identification and data capture techniques
• Current Stage: 6060 - International Standard published
• Start Date: 30-Oct-2026
• Completion Date: 30-Oct-2026

• Revises: ISO/IEC 18000-63:2021 - Information technology — Radio frequency identification for item management — Part 63: Parameters for air interface communications at 860 MHz to 960 MHz Type C
• Effective Date: 03-Jun-2023

ISO/IEC 18000-63 is the ISO/IEC standard for the RAIN air interface used by passive-backscatter radio frequency identification (RFID) systems in item management. It specifies how interrogators, also called readers, and tags, also called labels, communicate in the 860 MHz to 930 MHz range, including link parameters, commands, collision handling, and optional security. The standard is written for implementers who need interoperable RFID equipment and for users who need to check whether devices follow the same protocol.

What does ISO/IEC 18000-63 specify?

ISO/IEC 18000-63 specifies the air interface for RFID devices used in item management and describes the physical and logical rules for Interrogator-Talks-First (ITF) communication. It is a common technical specification that application standards can build on, so different products can work together in the same RFID environment.

The document is organized into:

• clauses for scope, references, terms, notation, conformance, the core protocol, and two optional extensions
• normative annexes for bit vectors, state machines, command-response tables, channelized signaling, error codes, slot counter operation, and sensor record structures
• informative annexes with examples, tutorials, calculation guidance, and background material

Annex	What it covers
A	Extensible bit vectors
B	State-transition tables
C	Command-response tables
D	Example slot-count parameter and Q selection
E	Example tag inventory and access
F	CRC-5 and CRC-16 calculation examples
G	Multiple- and dense-Interrogator channelized signaling
H	Interrogator-to-Tag link modulation waveforms
I	Tag error codes and their usage
J	Slot counter operation
K	Example data-flow exchange
L	Optional Tag features
M	Cryptographic suite checklist
N	Battery assisted Tag-to-Interrogator synchronization
O	Simple Sensors Data Block
P	Record structures and commands for Ported Simple Sensors
Q	BAP PIE and Manchester mode tutorial guide
R	Manchester mode RF power control
S	Additional information about RAIN

What are the key requirements of ISO/IEC 18000-63?

ISO/IEC 18000-63 defines a complete passive-backscatter protocol for tags and interrogators, including inventory, access, security, battery-assisted operation, and sensor extensions. In practice, this means a product must match the protocol timing, command formats, memory behavior, and optional feature rules if it claims conformance.

Conformance and extensibility

Clause 5 requires a device claiming conformance to follow all non-optional clauses and the associated conformance document, ISO/IEC 18047-63. It also notes that local radio regulations can limit the permitted operating parameters, so a product may still need regional regulatory review.

Clause 5.3 and 5.4 define how the protocol is extended. Mandatory, optional, proprietary, and custom commands are separated, and RFU values are reserved for future use and are not to be used for proprietary purposes. This matters because implementers need to avoid taking over reserved fields that future versions may assign.

Physical link and inventory operation

Clause 6 defines the physical layer and the operating procedure. The system uses half-duplex backscatter: the interrogator sends a continuous-wave (CW) field, and the tag answers by changing its antenna reflection coefficient. In practice, the interrogator powers the tag and also sets the timing and modulation that the tag must follow.

The inventory commands are Query, QueryX, QueryY, QueryAdjust, QueryRep, ACK, and NAK. Query and QueryX start an inventory round, and the fields DR, M, TRext, Sel, Session, Target, and Q control link rate, preamble behavior, selection, session, inventoried flag target, and slot count. This is the core of singulation: the interrogator controls how tags share the channel, and the tag responds only in its assigned slot.

Clause 6 also requires MSB-first transmission, CRC-16 and CRC-5 use for integrity, and fixed modulation, encoding, and data rate during an inventory round. The RTcal and TRcal timing symbols are used to determine symbol decisions and the backscatter link frequency (BLF). In practice, the device must decode timing correctly or it will not interpret commands and replies reliably.

Clause 6.3.1.4 and 6.3.1.7 also describe delayed replies and in-process replies. That is important for longer tag operations, because the tag may need to keep the interrogator informed while it is still processing a command.

Memory, access, and locking

Clause 6.3.2 defines the logical interface. The tag memory banks include Reserved, UII, TID, and User memory, and write operations are word-based. A Write uses link cover-coding and must be preceded by Req_RN so the interrogator can obscure the data with the fresh RN16 from the tag.

Locking is central to item-management use. Lock can lock or permanently lock passwords and memory areas such as the UII memory bank, TID memory bank, and File_0 of User memory. BlockPermalock permanently locks individual blocks in User memory. In practice, this lets a system decide which data can still be changed after commissioning and which data must stay fixed.

Clause 6 also defines ReadVar, ReadBuffer, FileOpen, FileList, FileSetup, and related commands. ReadBuffer is tied to the ResponseBuffer, which is used for certain longer replies and is read-only to the interrogator.

Security and protected communication

Clause 5.5 and clause 6.3.2.13.3 define the security model. The standard supports optional Authenticate, AuthComm, SecureComm, KeyUpdate, TagPrivilege, and Untraceable commands, and the Challenge and Authenticate commands use a cryptographic suite indicator (CSI). This lets a tag support one or more crypto suites and choose a specific one per command.

These commands support tag authentication, interrogator authentication, mutual authentication, authenticated communication, secure communication, key updating, and privilege control. Untraceable can hide memory, change the tag’s operating range, or do both when the interrogator has the required privilege. In practice, security is not a single feature - it is a set of commands that control identity checking, data confidentiality, and what the interrogator can see.

Optional BAP operation

Clause 7 adds battery assisted passive (BAP) operation. If a device supports any clause 7 feature, it must support the mandatory BAP behavior in that clause. BAP PIE improves sensitivity and robustness, and Battery Saver Mode can duty-cycle the tag receiver to save power.

Clause 7 also defines modified inventoried-flag persistence, signal-loss tolerance using INACT_T, and timeout behavior. It includes Manchester mode battery-assisted operation, Activation and Deactivation commands, Multirate_Reset, and op register access. For users, this means battery-assisted tags are not just passive tags with a battery - they follow additional state and timing rules.

Optional sensor support

Clause 8 adds sensor support for tags. It covers Snapshot Sensor, Simple Sensor, and Full Function Sensor behavior, and it uses XPC_W1 and the SA indicator for sensor-related status. Snapshot Sensors can measure on power-up or on demand, Simple Sensors append Simple Sensor Data (SSD) to the tag reply, and Full Function Sensors use the Sensor Directory System (SDS).

Clause 8 also defines the RTC, HandleSensor, and the record structures for ported simple sensors. In practice, this section is for tags that must carry sensor readings, expose alarm state, or support more structured sensor access.

What terms does ISO/IEC 18000-63 define?

• Air interface - the complete communication link between an interrogator and a tag, including the physical layer, collision arbitration, commands, responses, and data coding.
• Interrogator-Talks-First (ITF) - a communication mode where the tag responds only after the interrogator directs it to do so.
• Backscatter link frequency (BLF) - the frequency at which a tag modulates the backscattered signal.
• Inventory round - the period started by Query or QueryX and ended by a later Query, QueryX, Select, or Challenge.
• Handle - a 16-bit tag identifier used in access operations after singulation.
• Cryptographic Suite Indicator (CSI) - the field in Challenge and Authenticate that selects one cryptographic suite.
• Untraceable - a state or privilege that limits the identifying information a tag exposes, or limits its operating range, or both.
• Battery assisted passive (BAP) - a tag mode that uses a battery to improve operation while still using the RFID air interface.

Who uses ISO/IEC 18000-63?

ISO/IEC 18000-63 is used by RFID tag and interrogator manufacturers, protocol and firmware engineers, test laboratories, and system integrators building item-management systems. It is also relevant to quality teams and buyers who need to verify that different products can share the same air interface.

The standard matters wherever tags must be inventoried, selected, read, written, locked, authenticated, hidden, or extended with battery-assisted or sensor functions. It is especially useful when a project needs interoperable RAIN RFID behavior rather than a vendor-specific protocol.

What changed in ISO/IEC 18000-63 from the previous edition?

ISO/IEC 18000-63 is the fourth edition and it replaces ISO/IEC 18000-63:2021. The foreword lists these main changes:

• improved tag selection process
• a method to ensure tags are sufficiently energized before selection and communication
• a method for tag data reading
• QueryX and QueryY added to make the selection process more useful and robust
• ReadVar and the Read-User-Memory-bit (RUM) added to automate access to item attributes and the TID
• ResponseBuffer made optional

Which standards are used with ISO/IEC 18000-63?

• ISO/IEC 15961-1 - application interface for RFID item-management data
• ISO/IEC 15961-2 - registration of RFID data constructs
• ISO/IEC 15961-3 - RFID data constructs
• ISO/IEC 15962 - data encoding rules and logical memory functions
• ISO/IEC 15963-1 - unique identification for RF tags numbering systems
• ISO/IEC 18047-63 - conformance test methods for this air interface
• ISO/IEC 19762:2025 - vocabulary used for the terms and definitions
• ISO/IEC 29143 and ISO/IEC 29143:2011 - air interface specification for mobile RFID interrogators
• GS1 EPC Tag Data Standard (TDS) - reference for GS1 EPC tag data and the Extended Tag identifier (XTID)

What does the ISO/IEC 18000-63 document contain?

ISO/IEC 18000-63 contains command tables, reply formats, state-machine descriptions, timing rules, and link masks for the RAIN air interface. It also contains tables for memory-bank structure, XPC fields, error codes, CRC behavior, and sensor-related records.

The normative annexes provide the implementation data that engineers need when they code a reader or tag, while the informative annexes show examples, calculations, and tutorials. Annex B and Annex C are especially important for implementation and test work because they define state transitions and command-response behavior.

The document also includes figures and formulas for the RF envelopes, preambles, timing symbols, BLF relationships, and transmit masks used in single, multiple, and dense-interrogator environments. That makes it useful not only for protocol implementation, but also for validation, certification testing, and interoperability debugging.

International
Standard
ISO/IEC 18000-63
Fourth edition
Information technology — Radio
2026-10
frequency identification for item
management —
Part 63:
Parameters for air interface
communications at 860 MHz to 930
MHz Type C
Technologies de l'information — Identification par
radiofréquence (RFID) pour la gestion d'objets —
Partie 63: Paramètres de communications d'une interface radio
entre 860 MHz et 930 MHz, Type C
Reference number
© ISO/IEC 2026
All rights reserved.
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© ISO/IEC 2026 – All rights reserved
ii
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols, abbreviated terms and notations . 6
4.1 Symbols .6
4.2 Abbreviated terms .8
4.3 Notations .9
5 Conformance . 10
5.1 Claiming conformance .10
5.2 General conformance requirements .11
5.2.1 Interrogators .11
5.2.2 Tags.11
5.3 Command structure and extensibility . 12
5.3.1 General . 12
5.3.2 Mandatory commands . 12
5.3.3 Optional commands . . 12
5.3.4 Proprietary commands . 12
5.3.5 Custom commands . 12
5.4 Reserved for Future Use (RFU) . 12
5.5 Cryptographic Suite Indicators . 13
6 Protocol requirements .13
6.1 Protocol overview . 13
6.1.1 Physical layer . 13
6.1.2 Tag-identification layer . 13
6.2 Protocol parameters .14
6.2.1 Signaling — Physical and media access control parameters .14
6.2.2 Logical — Operating procedure parameters .16
6.3 Description of operating procedure .17
6.3.1 Physical interface .17
6.3.2 Logical interface .43
7 Battery assisted passive (BAP) Interrogator Talks First systems (optional) .139
7.1 Applicability . 139
7.2 General overview, descriptions and requirements of BAP . 139
7.3 BAP inventoried flag and state machine behaviour modifications .141
7.3.1 Modification to ready state and power-down support for BAP Tags .141
7.3.2 Signal loss tolerance via timer (mandatory) .142
7.3.3 Modified persistence of BAP PIE inventory flags (optional) . 144
7.4 BAP PIE (optional) . 146
7.4.1 Flex_Query command (optional) . . 146
7.4.2 BAP PIE detailed operation including optional Battery Saver Mode . 150
7.5 Manchester mode battery assisted operation protocol extensions . 156
7.5.1 General . 156
7.5.2 Physical layer . 156
7.5.3 Manchester activation . 163
7.5.4 Commands summary . 177
8 Sensor support (optional) .191
8.1 Applicability .191
8.2 Overview .191
8.3 Real Time Clock . . . 193
8.3.1 General . 193

© ISO/IEC 2026 – All rights reserved
iii
8.3.2 Setting the RTC . 193
8.3.3 BroadcastSync command (optional) . 193
8.3.4 Time synchronisation . 194
8.4 HandleSensor command (optional) . 195
8.5 Simple Sensors . 196
8.5.1 General . 196
8.5.2 Simple Sensor implementation . 196
8.6 Full Function Sensors and Sensor Directory System . 198
8.6.1 General . 198
8.6.2 Sensor Access — General approach. 198
8.7 Snapshot Sensors . 203
8.7.1 General . 203
8.7.2 Initiating Snapshot Sensor measurements . 205
8.7.3 Reporting Snapshot Sensor Information . 206
Annex A (normative) Extensible bit vectors . . 208
Annex B (normative) State-transition tables .210
Annex C (normative) Command-response tables .272
Annex D (informative) Example of a slot-count parameter, Q, selection algorithm . 300
Annex E (informative) Example of Tag inventory and access .301
Annex F (informative) Calculation of 5-bit and 16-bit cyclic redundancy checks .302
Annex G (normative) Multiple- and dense-Interrogator channelized signaling .305
Annex H (informative) Interrogator-to-Tag link modulation — Baseband waveforms,
modulated RF, and detected waveforms .307
Annex I (normative) Tag error codes and their usage . 309
Annex J (normative) Slot counter operation .310
Annex K (informative) Example data-flow exchange .311
Annex L (informative) Optional Tag features .314
Annex M (informative) Cryptographic suite checklist .317
Annex N (informative) Battery assisted Tag to Interrogator synchronization .318
Annex O (normative) Simple Sensors Data Block .321
Annex P (normative) Record structures and commands for Ported Simple Sensors .335
Annex Q (informative) BAP PIE and Manchester mode tutorial guide . 349
Annex R (informative) Manchester mode RF power control .359
Annex S (informative) Additional information about RAIN . 364
Bibliography .365

© ISO/IEC 2026 – All rights reserved
iv
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
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
committees established by the respective organization to deal with particular fields of technical activity.
ISO and IEC technical committees collaborate in fields of mutual interest. Other international organizations,
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The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of document should be noted. This document was drafted in accordance with the editorial rules of the ISO/
IEC Directives, Part 2 (see www.iso.org/directives or www.iec.ch/members_experts/refdocs).
ISO and IEC draw attention to the possibility that the implementation of this document may involve the
use of (a) patent(s). ISO and IEC take no position concerning the evidence, validity or applicability of any
claimed patent rights in respect thereof. As of the date of publication of this document, ISO and IEC had
received notice of (a) patent(s) which may be required to implement this document. However, implementers
are cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents and https://patents.iec.ch. ISO and IEC shall not be held
responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
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 31, Automatic identification and data capture techniques.
This fourth edition cancels and replaces the third edition (ISO/IEC 18000-63:2021), which has been
technically revised.
The main changes are as follows:
— tag selection process has been improved;
— a method to ensure tags are sufficiently energized before selection and communication has been added;
— a method for tag data reading has been provided;
— QueryX and QueryY has been added to make the selection process more topics useful and robust;
— ReadVar and Read-User-Memory-bit (RUM) automate the access to item attributes and the Tag Identifier
(TID);
— ResponseBuffer has been made optional.
A list of all parts in the ISO/IEC 18000 series can be found on the ISO and IEC websites.
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.

© ISO/IEC 2026 – All rights reserved
v
Introduction
A radio frequency identification (RFID) system comprises:
— Interrogators, also known as radio identification (RAIN) Readers, and
— RAIN Tags, also known as RAIN Labels or RAIN Transponders.
This document is also referred as RAIN Air Interface. For more information on RAIN, see Annex S.
A RAIN Interrogator transmits information to a RAIN Tag by modulating an RF signal in the 860 MHz to
930 MHz frequency range. The Tag receives both information and operating energy from this RF signal. Tags
are passive, which means that they receive all of their operating energy from the Interrogator’s RF signal.
A RAIN Interrogator receives information from a RAIN Tag by transmitting a continuous wave (CW) RF signal
to the Tag; the Tag responds by modulating the reflection coefficient of its antenna, thereby backscattering
an information signal to the Interrogator. The system is Interrogator-talks-first (ITF), which means that a
Tag modulates its antenna reflection coefficient with an information signal only after being directed to do so
by an Interrogator.
Interrogators and Tags are not required to talk simultaneously; rather, communications are half-duplex, i.e.
Interrogators talk and Tags listen, or vice versa.
The backscatter RFID system described in this document supports the following system capabilities:
— identification and communication with multiple tags in the field;
— selection of a subgroup of tags for identification or with which to communicate;
— reading from and writing to or rewriting data many times to individual tags;
— user-controlled permanently lockable memory;
— data integrity protection;
— Interrogator-to-Tag communications link with error detection;
— Tag-to-Interrogator communications link with error detection;
— support for both passive back-scatter tags with or without batteries.

© ISO/IEC 2026 – All rights reserved
vi
International Standard ISO/IEC 18000-63:2026(en)
Information technology — Radio frequency identification for
item management —
Part 63:
Parameters for air interface communications at 860 MHz to
930 MHz Type C
1 Scope
This document establishes the air interface for radio frequency identification (RFID) devices operating in the
860 MHz to 930 MHz industrial, scientific and medical (ISM) band used in item management applications.
This document specifies a common technical specification for RFID devices that can be used to develop
standards for applications using this radio identification (RAIN) air interface. This document is intended
to improve compatibility and encourage inter-operability of products for the growing RFID market in the
international marketplace.
This document establishes the forward and return link parameters for technical attributes including, but
not limited to, operating frequency, operating channel accuracy, occupied channel bandwidth, maximum
effective isotropic radiated power (EIRP), spurious emissions, modulation, duty cycle, data coding, bit rate,
bit rate accuracy, bit transmission order, and, where appropriate, operating channels, frequency hop rate,
hop sequence, spreading sequence, and chip rate. This document further specifies the communications
protocol used in the air interface.
This document describes the physical and logical requirements for a passive backscatter, Interrogator-talks-
first (ITF), radio frequency identification system operating in the 860 MHz to 930 MHz frequency range.
This document specifies:
— physical interactions (the signalling layer of the communication link) between Interrogators and Tags;
— logical operating procedures and commands between Interrogators and Tags;
— the collision arbitration scheme used to identify a specific tag in a multiple-tag environment;
[1]
— optional security commands that allow the use of crypto suites of ISO/IEC 29167-1:2014 .
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 15961-1, Information technology — Data protocol for radio frequency identification (RFID) for item
management — Part 1: Application interface
ISO/IEC 15961-2, Information technology — Data protocol for radio frequency identification (RFID) for item
management — Part 2: Registration of RFID data constructs
ISO/IEC 15961-3, Information technology — Data protocol for radio frequency identification (RFID) for item
management — Part 3: RFID data constructs

© ISO/IEC 2026 – All rights reserved
ISO/IEC 15962, Information technology — Radio frequency identification (RFID) for item management — Data
protocol: data encoding rules and logical memory functions
ISO/IEC 15963-1, Information technology — Radio frequency identification for item management — Part 1:
Unique identification for RF tags numbering systems
ISO/IEC 18047-63, Information technology — Radio frequency identification device conformance test methods
— Part 63: Test methods for air interface communications at 860 MHz to 960 MHz
ISO/IEC 19762:2025, Information technology — Automatic identification and data capture (AIDC) techniques
— Vocabulary
ISO/IEC 29143, Information technology — Automatic identification and data capture techniques — Air interface
specification for Mobile RFID interrogators
GS1 EPC Tag Data Standard (TDS), available at: https:// www .gs1 .org/ standards/ epc -rfid/ tds
ISO/IEC 18000-61, Information technology — Radio frequency identification for item management — Part 61:
Parameters for air interface communications at 860 MHz to 960 MHz Type A
ISO/IEC 18000-62, Information technology — Radio frequency identification for item management — Part 62:
Parameters for air interface communications at 860 MHz to 960 MHz Type B
ISO/IEC 18000-64, Information technology — Radio frequency identification for item management — Part 64:
Parameters for air interface communications at 860 MHz to 960 MHz Type D
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 19762:2025 and the following
apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
air interface
complete communication link between an Interrogator and a Tag including the physical layer, collision-
arbitration algorithm, command and response structure and data-coding methodology
3.2
authenticated communication
communication in which message integrity is protected
3.3
backscatter link frequency
frequency at which a Tag modulates the backscattered signal
3.4
battery assisted mode
working mode of battery assisted tags with non-empty battery
3.5
cover coding
method by which an Interrogator obscures information that it is transmitting to a Tag
Note 1 to entry: To cover-code data or a password, an Interrogator first requests a random number from the Tag.
The Interrogator then performs a bitwise exclusive OR (XOR) of the data or password with this random number, and
transmits the cover-coded string to the Tag. The Tag uncovers the data or password by performing a bitwise XOR of
the received cover-coded string with the original random number.

© ISO/IEC 2026 – All rights reserved
3.6
Extended Tag identifier
XTID
memory construct that defines a Tag’s capabilities and which can include a Tag serial number
[2]
Note 1 to entry: More information on XTID is provided in Reference .
3.7
extended temperature range
temperature range that is from –40 °C to +65 °C
3.8
file type
8-bit string that specifies a file’s designated type
3.9
file superuser
access password or key with a 0011 secured-state file privilege value
3.10
full-duplex communication
communication channel that carries data in both directions at once
Note 1 to entry: See half-duplex communications (3.12) for another option for bidirectional communication.
3.11
GS1 application ®
application whose usage denotes an acceptance of GS1 EPCglobal standards and policies
[3]
Note 1 to entry: Reference contains more details on GS1 application.
Note 2 to entry: See ISO application (3.17) for an alternative application option.
3.12
half-duplex communication
communication channel that carries data in one direction at a time rather than in both directions at once
Note 1 to entry: See full-duplex communications (3.10) for another option for bidirectional communication.
3.13
handle
16-bit tag identifier
3.14
hibernate
state of energy saving when the device is not required to be used
3.15
interrogator authentication
means for a Tag to determine, via cryptographic means, that an Interrogator’s identity is as claimed
3.16
inventory round
period initiated by a Query command or a QueryX command and terminated by either a subsequent Query
command, a subsequent QueryX command, a Select command or a Challenge command
3.17
ISO application
application whose usage denotes an acceptance of ISO standards and policies
Note 1 to entry: See GS1 application (3.11) for an alternative application option.

© ISO/IEC 2026 – All rights reserved
3.18
keyID
numerical designator for a single key
3.19
MAC
message authentication code
code, computed over bits in a message, that an Interrogator or a Tag can use to verify the integrity of the
message
3.20
mutual authentication
means for a Tag and an Interrogator to each determine, via cryptographic means, that the others’ identity is
as claimed
3.21
nominal temperature range
temperature range that is from –25 °C to +40 °C
Note 1 to entry: An extended temperature range (3.7) also exists.
3.22
non-removable Tag
Tag that a consumer cannot physically detach from an item without special equipment or without
compromising the item’s intended functionality
Note 1 to entry: In addition to a non-removeable tag, a removable Tag (3.25) also exists.
3.23
password
secret value sent by an Interrogator to a Tag to enable restricted Tag operations
Note 1 to entry: Passwords are not keys.
Note 2 to entry: The only passwords defined by the protocol defined in this document are the kill and access passwords.
3.24
Q
parameter that an Interrogator uses to regulate the probability of Tag response
Note 1 to entry: An Interrogator instructs Tags in an inventory round to load a Q-bit random (or pseudo-random)
number into their slot counter; the Interrogator can also command Tags to decrement their slot counter. Tags reply
when the value in their slot counter, i.e. their slot (3.30), is zero. Q is an integer in the range (0 to 15); the corresponding
0 –15
Tag-response probabilities range from 2 = 1 to 2 = 0,000031.
3.25
removable Tag
Tag that a consumer can physically detach from an item without special equipment and without
compromising the item’s intended functionality
Note 1 to entry: In addition to a removable Tag, a non-removable Tag (3.22) also exists.
3.26
secure communication
communication in which message confidentiality is protected
3.27
security
degree of protection against threats identified in a security policy
Note 1 to entry: A system is secure if it is protected to the degree specified in the security policy.

© ISO/IEC 2026 – All rights reserved
3.28
session key
temporary key generated by one or both of Tag and Interrogator and typically used for both authenticated
and secure communications
3.29
Simple Sensor functionality
functionality whereby a sensor provides a valid simple sensor data address and transmits simple sensor
data subsequent to the UII as part of the reply to the ACK command
3.30
slot
point in an inventory round (3.16) at which a Tag can respond
Note 1 to entry: Slot is the value output by a Tag’s slot counter; Tags reply when their slot (i.e. the value in their slot
counter) is zero.
Note 2 to entry: See Q (3.24) for the for the maximum number of slots.
3.31
snapshot sensor
sensor that makes a measurement during power-up or on demand from an Interrogator
3.32
Tag authentication
means for an Interrogator to determine, via cryptographic means, that a Tag’s identity is as claimed
3.33
traceable
not restricting the identifying information that a Tag exposes or the Tag’s operating range, or both
Note 1 to entry: To view the definition of the opposite term, refer to untraceable (3.36).
3.34
untraceable privilege
privilege given to the access password or to a key that grants an Interrogator using the access password or
key the right to access untraceably hidden memory (3.35) or to issue an untraceable (3.36) command, or both
3.35
untraceably hidden memory
memory that an untraceable Tag hides from Interrogators with a deasserted untraceable privilege (3.34)
3.36
untraceable
restricting the identifying information that a Tag exposes or the Tag’s operating range, or both
Note 1 to entry: To view the definition of the opposite term, refer to traceable (3.33).

© ISO/IEC 2026 – All rights reserved
4 Symbols, abbreviated terms and notations
4.1 Symbols
A numodulated field strength
A adjusted unmodulated field strength
adj
B modulated field strength
B adjusted modulated field strength
adj
C computed-response indicator
F file-services indicator (whether a Tag supports the FileOpen command)
f backscatter link frequency
BLF
FrT frequency tolerance
FS full function sensor indicator
H hazmat indicator
INACT_T inactivity threshold
K killable indicator
M number of subcarrier cycles per symbol
M RF field adjust downwards
adjd
M RF field adjust upwards
adju
M RF envelope ripple adjusted (overshoot)
adjh
M RF envelope ripple adjusted (undershoot)
adjl
M RF signal envelope ripple (overshoot)
h
M RF signal envelope ripple (undershoot)
l
M RF signal level when OFF
s
n divide ratio
DR
NR non-removable Tag indicator
Q slot-count parameter that is an integer in the range of 0 to 15
R=>T interrogator-to-tag (reader-to-tag)
RTcal interrogator-to-tag (reader-to-tag) calibration symbol
S security-services indicator
SA sensor alarm indictor
SLI SL indicator
SN snapshot sensor indicator
© ISO/IEC 2026 – All rights reserved
SS simple sensor indicator
T numbering system identifier
T=>R tag-to-Interrogator (tag-to-reader)
T time from Interrogator transmission to Tag response for an immediate Tag reply
T time from tag response to Interrogator transmission
T time an Interrogator waits, after T , before it issues another command
3 1
T minimum time between Interrogator commands
T time from Interrogator transmission to Tag response for a delayed Tag reply
T time from Interrogator transmission to first Tag response for an in-process Tag reply
T time between Tag responses for an in-process Tag reply
T time from end of QueryX or QueryY command to beginning of a subsequent QueryY
T time before command, power-up
cp
t RF signal envelope fall time
f,10-90 %
T fall time, power-down
fp
t RF adjust lag time
lag
t RF adjust lead time
lead
TN tag-notification indicator
T backscatter link pulse-repetition interval
pri
T or T RF signal envelope rise time
r r,10-90 %
T time between Interrogator command and Tag backscattered
REPLY
T rise time, power-up
rp
T settling time, power-up
sp
T time duration of RTcal
RTcal
T time duration of TRcal
TRcal
TRcal tag-to-Interrogator (tag-to-reader) calibration symbol
U untraceability indicator
RUM read user memory indicator
X XTID indicator (whether a Tag implements an XTID)
XEB XPC_W2 indicator
x floating-point value
fp
XI XPC_W1 indicator
© ISO/IEC 2026 – All rights reserved
xxxx binary notation
xxxx hexadecimal notation
h
4.2 Abbreviated terms
AC activation code
AFI application family identifier
AM amplitude modulation
ASIC application specific integrated circuit
BAM battery assisted mode
BAP battery assisted passive
BAT battery assisted tag
BLF backscatter link frequency
CSI cryptographic suite identifier
CW continuous wave
dBch decibels referenced to the integrated power in the reference channel
DBLF digital backscatter link frequency
DBR dead battery response
DR divide ratio
FDM frequency-division multiplexing
LPR low power receive
MAC message authentication code
MDID mask designer identifier
MSB most significant bit
NA not applicable
NoS number of sensors
NRZ Non-Return-to-Zero
OTP one-time programmable
PC protocol control
PIE pulse interval encoding
pivot decision threshold differentiating an R=>T data-0 symbol from a data-1 symbol
PM passive mode
ppm parts per million
© ISO/IEC 2026 – All rights reserved
PW pulse width
pwd password
R/W read or write
RAIN radio identification
RNG random or pseudo-random number generator
RO read only
RTC real time clock
SDS sensor directory system
SS simple sensor
SSB-ASK single-sideband amplitude-shift keying
SSD simple sensor data
TEDS transducer electronic data sheet
RUM read user memory indicator
UTC universal coordinated time
UWC User word count
XOR exclusive OR
XPC_W1 XPC word 1
XPC_W2 XPC word 2
XTID extended tag identifier
4.3 Notations
This document uses the following notational conventions.
— States and flags are denoted in bold. Some command parameters are also flags; a command parameter
used as a flag is denoted in bold.
EXAMPLE 1 ready.
— Command and Tag reply parameters are underlined. Some flags are also command parameters; a flag
used as a command parameter is underlined.
EXAMPLE 2 Pointer.
— Command parameters are given in upper case and Tag reply parameters are given in lower case.
EXAMPLE 3 Pointer and handle.
— Commands are denoted in italics.
NOTE As variables are also denoted in italics, where there can be confusion between commands and
variables, an explicit statement is added.
EXAMPLE 4 Query.
— For logical negation, labels are preceded by "~".

© ISO/IEC 2026 – All rights reserved
EXAMPLE 5 If flag is true, then ~flag is false.
— The symbol "⊗" refers to XOR.
— The symbol "||" refers to concatenation.
— The symbol "≠" refers to not equal.
— The symbol, "R=>T", refers to commands or signaling from an Interrogator to a Tag (Reader-to-Tag).
— The symbol, "T=>R", refers to commands or signaling from a Tag to an Interrogator (Tag-to-Reader).
— The numbering base is denoted with a subscript. Binary numbers are denoted with a subscript 2 (xxxx )
and hexadecimal numbers are denoted with a subscript h (xxxx ); the absence of a subscript denotes
h
decimal numbering system.
— The symbol "&" refers to bitwise Boolean and operation.
— The following term given in upper case "AND" refers to logical (true/false) and operation.
— The following term given in upper case "OR" refers to logical (true/false) or operation.
— When used in conditions, three or more logical conditions separated the symbol ";" share the same logical
operation.
EXAMPLE 6 A condition represented as “condition 1; condition 2; AND condition 3” is true if “condition 1 AND
condition 2 AND condition 3” is true.
The symbol ";" also represents three or more separate actions.
EXAMPLE 7 “action 1; action 2; and action 3” represents invoking of action 1, action 2 and action 3.
— The symbol "( and )" is used to clarify the order of evaluation for more complex conditions or actions.
EXAMPLE 8 A condition represented as “(condition 1 OR condition 2) AND condition3” is true if either
“condition 1 AND condition 3” or “condition 2 AND condition 3” is true.
— The term “address” is used as a synonym for “bit address”. All addresses specified are bit-addresses,
unless specified differently (e.g. by adding an according prefix such as “word” in “word address”).
The same applies for figures, where all shown addresses shall be interpreted as bit-addresses, unless
specified differently.
— The term “word” always refers to a 16-bit word.
5 Conformance
5.1 Claiming conformance
A device shall not claim conformance with this protocol unless the device is in accordance with
— all clauses in this protocol (except those marked as optional), and
— the conformance document associated with this protocol.
NOTE Local radio regulations can apply and can further limit some parameters defined in this document.
[4] [5]
Relevant conformance test methods are provided in ISO/IEC 18047-6 and ISO/IEC 18047-63 .
A device claiming conformance shall pass the conformance tests the conformance document
ISO/IEC 18047-63.
Conformance can also require a license from the owner of any intellectual property utilized by said device.

© ISO/IEC 2026 – All rights reserved
[6] [7]
Optional performance test methods are provided in ISO/IEC 18046-1:2011 , ISO/IEC 18046-3:2020 and
[8]
ISO/IEC 18046-2:2020 .
5.2 General conformance requirements
5.2.1 Interrogators
To conform to this document, an Interrogator shall:
— meet the requirements of this document;
— implement the mandatory commands defined in this document;
— modulate (transmit) and demodulate (receive) a sufficient set of the electrical signals defined in the
signaling layer of this protocol to communicate with conformant Tags.
Optionally, an Interrogator can:
— implement any subset of the optional commands defined in this document;
— implement any proprietary or custom commands, or both, according to this document.
To conform to this document, an Interrogator shall not:
— implement any command that conflicts with this document, or ISO/IEC 18000-61, ISO/IEC 18000-62 and
ISO/IEC 18000-64;
— require using an optional, proprietary or custom command to meet the requirements of this protocol.
5.2.2 Tags
To conform to this document, a Tag shall:
— meet the requirements of this document;
— implement the mandatory commands defined in this document;
— modulate a backscatter signal only after receiving the requisite command from an Interrogator.
Optionally, a Tag can:
— implement any of the optional Tag features in Clause 7, Clause 8 and Annex L;
— implement any subset of the optional commands defined in this document;
— implement any proprietary or custom, or both commands as defined in 5.3.4 and 5.3.5, respectively.
To conform to this document, a Tag shall not:
— implement any command that conflicts with this document, or ISO/IEC 18000-61, ISO/IEC 18000-62 and
ISO/IEC 18000-64;
— require using an optional, proprietary or custom command to meet the requirements of this protocol;
— modulate a backscatter signal unless commanded to do so by an Interrogator using the signaling layer
defined in this document.
© ISO/IEC 2026 – All rights reserved
5.3 Command structure and extensibility
5.3.1 General
This document allows four command types:
a) mandatory,
b) optional,
c) proprietary, and
...