ISO/IEC 14443-3:2018

INTERNATIONAL ISO/IEC
STANDARD 14443-3
Fourth edition
2018-07
Cards and security devices for
personal identification — Contactless
proximity objects —
Part 3:
Initialization and anticollision
Cartes et dispositifs de sécurité pour l'identification personnelle —
Objets sans contact de proximité —
Partie 3: Initialisation et anticollision
Reference number
©
ISO/IEC 2018
© ISO/IEC 2018
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Published in Switzerland
ii © ISO/IEC 2018 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols, abbreviated terms and notations . 3
4.1 Symbols and abbreviated terms. 3
4.2 Notations . 5
5 General requirements . 5
5.1 Alternating PICC and PCD support (PXD) . 5
5.2 Alternating between Type A and Type B commands . 5
5.2.1 Polling . . 5
5.2.2 Influence of Type A commands on PICC Type B operation . 6
5.2.3 Influence of Type B commands on PICC Type A operation . 6
5.2.4 Transition to POWER-OFF state . 7
5.3 RFU handling . 7
6 Type A — Initialization and anticollision . 7
6.1 etu . 7
6.2 Frame format and timing . 7
6.2.1 Frame delay time . 8
6.2.2 Request Guard Time . 9
6.2.3 Frame formats .10
6.2.4 CRC_A .12
6.3 PICC states .12
6.3.1 POWER-OFF state.13
6.3.2 IDLE state .14
6.3.3 READY state.14
6.3.4 ACTIVE state .14
6.3.5 HALT state .14
6.3.6 READY* state .14
6.3.7 ACTIVE* state.15
6.3.8 PROTOCOL state .15
6.4 Command set .15
6.4.1 REQA and WUPA commands .15
6.4.2 ANTICOLLISION and SELECT commands .16
6.4.3 HLTA command .16
6.5 Select sequence . .17
6.5.1 Select sequence flowchart .17
6.5.2 ATQA — Answer to Request .17
6.5.3 Anticollision and Select .18
6.5.4 UID contents and cascade levels .21
7 Type B — Initialization and anticollision .23
7.1 Character, frame format and timing .23
7.1.1 Character transmission format .23
7.1.2 Character separation .23
7.1.3 Frame format .24
7.1.4 SOF .24
7.1.5 EOF .25
7.1.6 Timing before the PICC SOF .26
7.1.7 Timing before the PCD SOF .26
7.2 CRC_B . .27
7.3 Anticollision sequence .27
© ISO/IEC 2018 – All rights reserved iii

7.4 PICC states description .28
7.4.1 Initialization and anticollision flowchart .30
7.4.2 General statement for state description and transitions .30
7.4.3 POWER-OFF state.31
7.4.4 IDLE state .31
7.4.5 READY-REQUESTED sub-state .31
7.4.6 READY-DECLARED sub-state .31
7.4.7 PROTOCOL state .32
7.4.8 HALT state .32
7.5 Command set .32
7.6 Anticollision response rules .32
7.6.1 PICC with initialization only .33
7.7 REQB/WUPB command .33
7.7.1 REQB/WUPB command format .33
7.7.2 Coding of anticollision prefix byte APf .33
7.7.3 Coding of AFI .33
7.7.4 Coding of PARAM .34
7.8 Slot-MARKER command .35
7.8.1 Slot-MARKER command format .35
7.8.2 Coding of anticollision prefix byte APn .35
7.9 ATQB Response .36
7.9.1 ATQB response format .36
7.9.2 Pseudo-Unique PICC Identifier (PUPI) .36
7.9.3 Application data .36
7.9.4 Protocol Info .37
7.10 ATTRIB command .40
7.10.1 ATTRIB command format .40
7.10.2 Identifier .40
7.10.3 Coding of Param 1 .40
7.10.4 Coding of Param 2 .42
7.10.5 Coding of Param 3 .42
7.10.6 Coding of Param 4 .43
7.10.7 Higher layer INF .43
7.11 Answer to ATTRIB command .43
7.12 HLTB command and Answer .44
8 Electromagnetic disturbance handling .44
8.1 General .44
8.2 EMD timing constraints .45
8.3 Recommendations for a PCD algorithm for EMD handling .46
Annex A (informative) Communication example Type A .47
Annex B (informative) CRC_A and CRC_B encoding .50
Annex C (informative) Type A timeslot — Initialization and anticollision .53
Bibliography .57
iv © ISO/IEC 2018 – All rights reserved

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, governmental and non-governmental, in liaison with ISO and IEC, also take part in the
work. In the field of information technology, ISO and IEC have established a joint technical committee,
ISO/IEC JTC 1.
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).
Attention is drawn to the possibility that some of the elements of this document may be the subject
of patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent
rights. Details of any patent rights identified during the development of the document will be in the
Introduction and/or on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on 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 the following
URL: www .iso .org/iso/foreword .html.
This document was prepared by ISO/IEC JTC 1, Information technology, Subcommittee SC 17, Cards and
security devices for personal identification.
This fourth edition cancels and replaces the third edition (ISO/IEC 14443-3:2016), which has been
technically revised.
The following are the main changes since the last edition:
— RFU handling rules and clarifications have been added;
— Annexes D and E have been removed.
A list of all the parts in the ISO/IEC 14443 series can be found on the ISO website.
© ISO/IEC 2018 – All rights reserved v

Introduction
The ISO/IEC 14443 series of standards describes the parameters for identification cards or objects for
international interchange.
This document describes polling for proximity cards entering the field of a proximity coupling device,
the byte format and framing, the initial Request and Answer to Request command content, methods to
detect and communicate with one proximity card among several proximity cards (anticollision) and
other parameters required to initialize communications between a proximity card and a proximity
coupling device. Protocols and commands used by higher layers and by applications and which are used
after the initial phase are described in ISO/IEC 14443-4.
The ISO/IEC 14443 series of standards is intended to allow operation of proximity cards in the presence
of other contactless cards or objects conforming to the ISO/IEC 10536 series of standards and the ISO/
IEC 15693 series of standards and near field communication (NFC) devices conforming to ISO/IEC
18092 and ISO/IEC 21481.
vi © ISO/IEC 2018 – All rights reserved

INTERNATIONAL STANDARD ISO/IEC 14443-3:2018(E)
Cards and security devices for personal identification —
Contactless proximity objects —
Part 3:
Initialization and anticollision
1 Scope
This document describes the following:
— polling for proximity cards or objects (PICCs) entering the field of a proximity coupling device (PCD);
— the byte format, the frames and timing used during the initial phase of communication between
PCDs and PICCs;
— the initial Request and Answer to Request command content;
— methods to detect and communicate with one PICC among several PICCs (anticollision);
— other parameters required to initialize communications between a PICC and PCD;
— optional means to ease and speed up the selection of one PICC among several PICCs based on
application criteria;
— optional capability to allow a device to alternate between the functions of a PICC and a PCD to
communicate with a PCD or a PICC, respectively. A device which implements this capability is
called a PXD.
Protocol and commands used by higher layers and by applications and which are used after the initial
phase are described in ISO/IEC 14443-4.
This document is applicable to PICCs of Type A and of Type B (as described in ISO/IEC 14443-2), to PCDs
(as described in ISO/IEC 14443-2) and to PXDs.
NOTE 1 Part of the timing of data communication is defined in ISO/IEC 14443-2.
NOTE 2 Test methods for this document are defined in ISO/IEC 10373-6.
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 7816-4, Identification cards — Integrated circuit cards — Part 4: Organization, security and
commands for interchange
ISO/IEC 7816-6, Identification cards — Integrated circuit cards — Part 6: Interindustry data elements for
interchange
ISO/IEC 13239, Information technology — Telecommunications and information exchange between
systems — High-level data link control (HDLC) procedures
ISO/IEC 14443-2, Cards and security devices for personal identification — Contactless proximity objects
—Part 2: Radio frequency power and signal interface
© ISO/IEC 2018 – All rights reserved 1

ISO/IEC 14443-4, Cards and security devices for personal identification — Contactless proximity objects
—Part 4: Transmission protocol
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 14443-2 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http: //www .electropedia .org/
— ISO Online browsing platform: available at https: //www .iso .org/obp
3.1
anticollision loop
algorithm used to prepare for dialogue between PCD and one or more PICCs out of the total number of
PICCs responding to a request command
3.2
byte
8 bits of data designated b8 to b1, from the most significant bit (MSB, b8) to the least significant bit
(LSB, b1)
3.3
collision
transmission by two PICCs in the same PCD energizing field and during the same time period, such that
the PCD is unable to distinguish from which PICC the data originated
3.4
frame
sequence of data bits and optional error detection bits, with frame delimiters at start and end
3.5
frame error
error on SOF, start and stop bits, parity bits, EOF
3.6
higher layer protocol
protocol layer (not described in this document) that makes use of the protocol layer defined in this
document to transfer information belonging to the application or higher layers of protocol that is not
described in this document
3.7
PCD Mode
mode in which a PXD operates as a PCD
3.8
PICC Mode
mode in which a PXD operates as a PICC
3.9
request command
command requesting PICCs of the appropriate type to respond if they are available for initialization
3.10
transmission error
frame error or CRC_A or CRC_B error
2 © ISO/IEC 2018 – All rights reserved

4 Symbols, abbreviated terms and notations
4.1 Symbols and abbreviated terms
ADC Application Data Coding, Type B
AFI Application Family Identifier, card preselection criteria by application, Type B
APf anticollision prefix f, used in REQB/WUPB, Type B
APn anticollision prefix n, used in Slot-MARKER command, Type B
ATQA Answer to Request, Type A
ATQB Answer to Request, Type B
ATTRIB PICC selection command, Type B
BCC Block Check Character (UID CLn check byte), Type A
CID Card Identifier
CLn cascade level n, Type A
CT cascade tag, Type A
CRC_A Cyclic Redundancy Check error detection code, Type A
CRC_B Cyclic Redundancy Check error detection code, Type B
D Divisor
E end of communication, Type A
EGT extra guard time, Type B
EOF end of frame, Type B
etu elementary time unit
FDT frame delay time PCD to PICC, Type A
fc carrier frequency
FO Frame Option, Type B
fs subcarrier frequency
FWI Frame Waiting time Integer
FWT Frame Waiting Time
HLTA halt command, Type A
HLTB halt command, Type B
ID identification number, Type A
INF information field belonging to higher layer, Type B
LSB least significant bit
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MBL Maximum Buffer Length, Type B
MBLI Maximum Buffer Length Index, Type B
MSB most significant bit
N number of anticollision slots, Type B
n variable integer value as defined in the specific clause
NAD node address
NVB number of valid bits, Type A
P odd parity bit, Type A
PCD proximity coupling device
PICC proximity card or object
PUPI Pseudo-Unique PICC Identifier, Type B
PXD proximity extended device
R slot number chosen by the PICC during the anticollision sequence, Type B
REQA REQuest command, Type A
REQB REQuest command, Type B
RFU reserved for future use
S start of communication, Type A
SAK Select acknowledge, Type A
SEL select code, Type A
SELECT SELECT command, Type A
SFGI Start-up Frame Guard time Integer
SFGT Start-up Frame Guard Time
SOF Start Of Frame, Type B
t maximum automatic mode alternation cycle time
cyc
t minimum time difference of PICC Mode durations
diff
t low EMD time, PICC
E, PICC
t low EMD time, PCD
E, PCD
TR0 guard time as defined in ISO/IEC 14443-2, Type B
TR1 synchronization time as defined in ISO/IEC 14443-2, Type B
TR2 frame delay time PICC to PCD, Type B
UID unique identifier, Type A
4 © ISO/IEC 2018 – All rights reserved

UID CLn unique identifier of CLn, Type A
uidn byte number n of unique identifier, n ≥ 0
WUPA Wake-UP command, Type A
WUPB Wake-UP command, Type B
4.2 Notations
—  (xxxxx)b data bit representation
—  'XY' hexadecimal notation, equal to XY to the base 16
5 General requirements
5.1 Alternating PICC and PCD support (PXD)
A proximity extended device (PXD) shall alternately support PICC requirements (PICC Mode) and PCD
requirements (PCD Mode).
The alternation between the PICC Mode and the PCD Mode may be either automatic or a Mode (PICC
Mode or PCD Mode) may be explicitly selected by the user.
The PICC Mode and the PCD Mode are defined as PICC and PCD in the ISO/IEC 14443 series of standards.
The automatic alternation is defined as follows:
— the PXD shall alternate between the PICC Mode and the PCD Mode with maximum cycle time t = 1 s
cyc
and shall stay in PICC Mode (ready for receiving REQA/WUPA or REQB/WUPB commands, except
for the first 5 ms) longer than in PCD Mode (generating operating field), until a communication to
either a PICC, a PCD or another PXD is established;
— the PXD shall randomly set the PICC Mode duration for each cycle to a value chosen from a set of at
least two different values differing by at least t = 5 ms between each of them;
diff
— in PICC Mode, after reception of a valid REQA/WUPA or REQB/WUPB command, the PXD shall not
go in PCD Mode before a POWER-OFF state;
— when leaving the PCD Mode after processing of a PICC (or a PXD in PICC mode), the PXD shall resume
its automatic mode alternation with the PICC Mode first.
The PXD may check the presence of external operating field to decide not to enter PCD Mode, i.e. to stay
in PICC Mode for a further random PICC Mode duration.
The detection of the removal of a PICC (or PXD in PICC Mode) should be done by a PICC presence check
method without switching off the operating field to keep the same UID/PUPI and to avoid PXD entering
the PCD Mode.
5.2 Alternating between Type A and Type B commands
5.2.1 Polling
In order to detect PICCs which are in the operating field, the PCD shall send repeated request
commands. The PCD shall send REQA (or WUPA) and REQB (or WUPB) in any sequence using an
equal or configurable duty cycle when polling Type A and Type B. In addition, the PCD may send other
commands as described in Annex C.
© ISO/IEC 2018 – All rights reserved 5

When a PICC is exposed to an unmodulated RF field (see ISO/IEC 14443-2), it shall be able to accept a
request within 5 ms.
EXAMPLE 1
When a PICC Type A receives any Type B command, it shall be able to accept a REQA (or WUPA) within
5 ms of unmodulated RF field.
EXAMPLE 2
When a PICC Type B receives any Type A command, it shall be able to accept a REQB (or WUPB) within
5 ms of unmodulated RF field.
EXAMPLE 3
When a PICC Type A is exposed to field activation, it shall be able to accept a REQA (or WUPA) within
5 ms of unmodulated RF field.
EXAMPLE 4
When a PICC Type B is exposed to field activation, it shall be able to accept a REQB (or WUPB) within
5 ms of unmodulated RF field.
EXAMPLE 5
When a PICC supporting Type A and Type B is exposed to field activation, it shall be able to accept a
REQA (or WUPA) within 5 ms of unmodulated RF field.
EXAMPLE 6
When a PICC supporting Type A and Type B is exposed to field activation, it shall be able to accept a
REQB (or WUPB) within 5 ms of unmodulated RF field.
In order to detect PICCs requiring 5 ms, the PCD should periodically present an unmodulated RF field of
at least 5,1 ms duration (prior to both Type A and Type B request commands), but may poll more rapidly
because PICCs may react faster.
If the PICC supports Type A and Type B, then it shall be locked in the type of the first processed request
command (after Answer to Request of one type, the other type is disabled until the PICC enters POWER-
OFF state).
The PCD may need to adapt its polling cycle if it wants to detect such a PICC in the disabled type.
5.2.2 Influence of Type A commands on PICC Type B operation
A PICC Type B shall either go to IDLE state (be able to accept a REQB) or be able to continue a transaction
in progress after receiving any Type A frame.
A PICC Type B should have the same behavior after receiving any frame of any other standard using the
same carrier frequency.
5.2.3 Influence of Type B commands on PICC Type A operation
A PICC Type A shall either go to IDLE state (be able to accept a REQA) or be able to continue a transaction
in progress after receiving any Type B frame. If the PICC Type A is in READY* or ACTIVE* state when
receiving any Type B frame, it may also go to HALT state as described in Figure 7.
A PICC Type A should have the same behavior after receiving any frame of any other standard using the
same carrier frequency.
6 © ISO/IEC 2018 – All rights reserved

5.2.4 Transition to POWER-OFF state
The PICC shall be in POWER-OFF state no later than 5 ms after the operating field is switched off.
5.3 RFU handling
For the purposes of this document, the following general rules apply.
— A PICC or PCD sending RFU bits shall set these bits to the value indicated herein or to (0)b if no value
is given.
— A PICC or PCD receiving RFU bits shall ignore the value of these bits and shall maintain and not
change its function, unless explicitly stated otherwise.
6 Type A — Initialization and anticollision
6.1 etu
The value of the etu for each bit rate is defined in Table 1.
Table 1 — etu
Bit rate etu
fc/128 (~ 106 kbit/s) 128/fc (~ 9,4 µs)
fc/64 (~ 212 kbit/s) 64/fc (~ 4,7 µs)
fc/32 (~ 424 kbit/s) 32/fc (~ 2,4 µs)
fc/16 (~ 848 kbit/s) 16/fc (~ 1,2 µs)
fc/8 (~ 1,70 Mbit/s) 8/fc (~ 0,59 µs)
fc/4 (~ 3,39 Mbit/s) 4/fc (~ 0,29 µs)
fc/2 (~ 6,78 Mbit/s) 2/fc (~ 0,15 µs)
3fc/4 (~ 10,17 Mbit/s) 4/fc (~ 0,29 µs)
fc (~ 13,56 Mbit/s) 4/fc (~ 0,29 µs)
3fc/2 (~ 20,34 Mbit/s) 2/fc (~ 0,15 µs)
2fc (~ 27,12 Mbit/s) 2/fc (~ 0,15 µs)
6.2 Frame format and timing
This subclause defines the frame format and timing used during communication initialization and
anticollision. For bit representation and coding, refer to ISO/IEC 14443-2.
Frames shall be transferred in pairs, PCD to PICC followed by PICC to PCD, using the following sequence:
— PCD frame:
— PCD start of communication;
— information and, where required, error detection bits sent by the PCD;
— PCD end of communication;
— Frame delay time PCD to PICC;
— PICC frame:
— PICC start of communication;
— information and, where required, error detection bits sent by the PICC;
© ISO/IEC 2018 – All rights reserved 7

— PICC end of communication;
— Frame delay time PICC to PCD.
NOTE The frame delay time (FDT) from PCD to PICC overlaps the PCD end of communication.
6.2.1 Frame delay time
The frame delay time is defined as the time between two frames transmitted in opposite directions.
6.2.1.1 Frame delay time PCD to PICC
This is the time between the end of the last pause transmitted by the PCD and the first modulation edge
within the start bit transmitted by the PICC and shall respect the timing defined in Figure 1 and Table 2
where n is an integer value.
For bit rates of fc/8, fc/4 and fc/2, the FDT starts at the end of the last modulation transmitted by the PCD.
For bit rates of 3fc/4, fc, 3fc/2, and 2fc, the FDT starts at the end of the last phase modulation transmitted
by the PCD.
Table 2 defines values for n and FDT depending on the command type and the logic state of the last
transmitted data bit in this command.
Figure 1 — Frame delay time PCD to PICC for bit rates up to fc/16
NOTE t is specified in Clause 8.
E, PICC
8 © ISO/IEC 2018 – All rights reserved

Table 2 — Frame delay time PCD to PICC
FDT
Command type n (integer value)
last bit = (1)b last bit = (0)b
REQA command 9 (n × 128 + 84)/fc (n × 128 + 20)/fc
WUPA command [ = 1 236/fc ] [ = 1 172/fc ]
ANTICOLLISION command
SELECT command
All other commands at bit rates
PCD to PICC PICC to PCD
fc/128 ≥9 (n × 128 + 84)/fc (n × 128 + 20)/fc
fc/64 ≥8 (n × 128 + 148)/fc (n × 128 + 116)/fc
fc/128
fc/32 ≥8 (n × 128 + 116)/fc (n × 128 + 100)/fc
fc/16 ≥8 (n × 128 + 100)/fc (n × 128 + 92)/fc
fc/128 or fc/64 or Not applicable ≥1 116/fc ≥1 116/fc
fc/32 or fc/16 or fc/8 fc/64 or fc/32 or fc/16
or fc/4 or fc/2 or 3fc/4 or fc/8 or fc/4 or fc/2
or fc or 3fc/2 or 2fc
For anticollision, all PICCs in the field shall respond in a synchronous way to the commands: REQA, WUPA, ANTICOLLISION
and SELECT.
If a bit rate higher than fc/16 is selected for PCD to PICC communication, then a bit rate of fc/128 is not
allowed for PICC to PCD communication, see ISO/IEC 14443-4. This restriction is required because the
necessary precise FDT is not defined for PCD NRZ-L coding which is used for bit rates higher than fc/16.
The FDT measurement starts at the beginning of the rising edge as specified and illustrated with small
1)
circles in the following figures of ISO/IEC 14443-2:— :
— Figure titled “PauseA for a bit rate of fc/128” for PCD to PICC bit rate of fc/128;
— Figure titled “PauseA for bit rates of fc/64, fc/32, and fc/16” for PCD to PICC bit rates of fc/64, fc/32
and fc/16;
— Figure titled “Type B modulation waveform” for PCD to PICC bit rates of fc/8, fc/4 and fc/2.
The measured FDT shall be between the value given in Table 2 and the value given in Table 2 + 0,4 µs.
The PCD should accept a response with a FDT tolerance of −1/fc to (+0,4 µs + 1/fc).
6.2.1.2 Frame delay time PICC to PCD
This is the time between the last modulation transmitted by the PICC and the first modulation
transmitted by the PCD and shall be at least 1 172/fc.
To enhance interoperability, an additional waiting time of 100/fc should be incorporated in the PCD
operation.
6.2.2 Request Guard Time
The Request Guard Time is defined as the minimum time between the start bits of two consecutive
REQA or WUPA commands. It has the value 7 000/fc.
To enhance interoperability, an additional waiting time of 100/fc should be incorporated in the PCD
operation.
1) Fourth edition to be published.
© ISO/IEC 2018 – All rights reserved 9

6.2.3 Frame formats
The following frame types are defined:
— short frames;
— standard frames;
— bit oriented anticollision frame;
— PCD standard frames for bit rates of fc/8, fc/4 and fc/2.
6.2.3.1 Short frame
A short frame is used to initiate communication and consists of, in the following order as illustrated in
Figure 2:
— start of communication;
— 7 data bits transmitted LSB first (for coding see Table 3);
— end of communication.
No parity bit is added.
Figure 2 — Short frame
6.2.3.2 Standard frames
6.2.3.2.1 PCD standard frame for bit rates of fc/128, fc/64, fc/32 and fc/16 and PICC
standard frame
Standard frames are used for data exchange and consist of, in the following order:
— start of communication;
— n × (8 data bits + odd parity bit), with n ≥ 1. The LSB of each byte is transmitted first. Each byte is
followed by an odd parity bit. The parity bit P is set such that the number of 1s is odd in (b1 to b8, P);
— end of communication.
The PCD standard frame for bit rates of fc/128, fc/64, fc/32 and fc/16 is illustrated in Figure 3.
Figure 3 — PCD standard frame for bit rates of fc/128, fc/64, fc/32 and fc/16
As an exception, the last parity bit of a PICC standard frame shall be inverted if this frame is transmitted
with a bit rate higher than fc/128. PICC standard frames are illustrated in Figure 4.
10 © ISO/IEC 2018 – All rights reserved

Figure 4 — PICC standard frames for all bit rates
6.2.3.2.2 PCD standard frame for bit rates of fc/8, fc/4 and fc/2
The character transmission format and character separation as defined in 7.1.1 and 7.1.2, respectively,
shall be used.
The frame format is defined in 7.1.3.
6.2.3.2.3 PCD standard frame for PCD to PICC bit rates of 3fc/4, fc, 3fc/2 and 2fc
The standard frame format as defined in 6.2.3.2.1 shall be used.
Start and end of communication are specified in ISO/IEC 14443-2.
6.2.3.3 Bit oriented anticollision frame
The PCD shall detect a collision that occurs when at least two PICCs simultaneously transmit bit
patterns with one or more bit positions in which at least two PICCs transmit complementary values. In
this case, the bit patterns merge and the carrier is modulated with the subcarrier for the whole (100%)
bit duration (see ISO/IEC 14443-2:—, 8.2.5.1).
Bit oriented anticollision frames shall only be used during bit frame anticollision loops and are standard
frames with a length of 7 bytes, split into the following two parts:
— part 1 for transmission from PCD to PICC;
— part 2 for transmission from PICC to PCD.
For the length of part 1 and part 2, the following rules shall apply:
— Rule 1: The sum of data bits shall be 56.
— Rule 2: The minimum length of part 1 shall be 16 data bits.
— Rule 3: The maximum length of part 1 shall be 48 data bits.
Consequently, the minimum length of part 2 shall be 8 data bit and the maximum length shall be
40 data bits.
Since the split can occur at any bit position within a byte, the following two cases are defined:
— case FULL BYTE: Split after a complete byte. A parity bit is added after the last data bit of part 1;
— case SPLIT BYTE: Split within a byte. No parity bit is added after the last data bit of part 1.
© ISO/IEC 2018 – All rights reserved 11

The Block Check Characters (BCC) is calculated as exclusive-or over the four previous bytes.
The following examples for case FULL BYTE and case SPLIT BYTE define the bit organization and order
of bit transmission, illustrated in Figure 5 and Figure 6.
NOTE These examples include proper values for NVB and BCC.
Figure 5 — Bit organization and transmission of bit oriented anticollision frame, case FULL BYTE
Figure 6 — Bit organization and transmission of bit oriented anticollision frame, case SPLIT BYTE
For a SPLIT BYTE, the PCD shall ignore the first parity bit of part 2.
6.2.4 CRC_A
A frame that includes CRC_A shall only be considered correct if it is received with a valid CRC_A value.
The frame CRC_A is a function of k data bits, which consist of all the data bits in the frame, excluding parity
bits, S and E, and the CRC_A itself. Since data is encoded in bytes, the number of bits k is a multiple of 8.
For error checking, the two CRC_A bytes are sent in the standard frame, after the data bytes and before
the E. The CRC_A shall be as defined in ISO/IEC 13239 but the initial register content shall be '6363' and
the register content shall not be inverted after calculation.
For examples, refer to Annex B.
6.3 PICC states
The following subclauses provide descriptions of the states for a PICC Type A specific to the anticollision
sequence.
12 © ISO/IEC 2018 – All rights reserved

The state diagram in Figure 7 specifies all possible state transitions caused by commands of this part
of ISO/IEC 14443. PICCs shall react to valid received frames only. No response shall be sent when
transmission errors are detected except for PICCs in ACTIVE or ACTIVE* state.
Figure 7 — PICC Type A state diagram
The following symbols apply for the state diagram shown in Figure 7:
AC: ANTICOLLISION command (matched UID)
nAC: ANTICOLLISION command (not matche
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