EN ISO/IEC 15438:2010

SLOVENSKI STANDARD
01-oktober-2010
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SIST EN ISO/IEC 15438:2003
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Information technology - Automatic identification and data capture techniques - PDF417
bar code symbology specification (ISO/IEC 15438:2006)
Informationstechnik - Verfahren der automatischen Identifikation und Datenerfassung -
Spezifikationen für Strichcodesystembologien: PDF 417 (ISO/IEC 15438:2006)
Technologies de l'information - Techniques automatiques d'identification et de capture
des données - Spécifications pour la symbologie de code à barres PDF417 (ISO/IEC
15438:2006)
Ta slovenski standard je istoveten z: EN ISO/IEC 15438:2010
ICS:
35.040 Nabori znakov in kodiranje Character sets and
informacij information coding
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO/IEC 15438
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2010
ICS 35.040 Supersedes EN ISO/IEC 15438:2003
English Version
Information technology - Automatic identification and data
capture techniques - PDF417 bar code symbology specification
(ISO/IEC 15438:2006)
Technologies de l'information - Techniques automatiques Informationstechnik - Verfahren der automatischen
d'identification et de capture des données - Spécifications Identifikation und Datenerfassung - Spezifikation der
pour la symbologie de code à barres PDF417 (ISO/IEC Strichcodesymbologie PDF417 (ISO/IEC 15438:2006)
15438:2006)
This European Standard was approved by CEN on 29 July 2010.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO/IEC 15438:2010: E
worldwide for CEN national Members.

Contents Page
Foreword .3

Foreword
The text of ISO/IEC 15438:2006 has been prepared by Technical Committee ISO/IEC JTC 1 “Information
technology” of the International Organization for Standardization (ISO) and the International Electrotechnical
Commission (IEC) and has been taken over as EN ISO/IEC 15438:2010 by Technical Committee
CEN/TC 225 “AIDC technologies” the secretariat of which is held by NEN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by February 2011, and conflicting national standards shall be withdrawn
at the latest by February 2011.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO/IEC 15438:2003.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO/IEC 15438:2006 has been approved by CEN as a EN ISO/IEC 15438:2010 without any
modification.
INTERNATIONAL ISO/IEC
STANDARD 15438
Second edition
2006-06-01
Information technology — Automatic
identification and data capture
techniques — PDF417 bar code
symbology specification
Technologies de l'information — Techniques d'identification
automatique et de capture des données — Spécifications pour la
symbologie de code à barres PDF417

Reference number
ISO/IEC 15438:2006(E)
©
ISO/IEC 2006
ISO/IEC 15438:2006(E)
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ii © ISO/IEC 2006 – All rights reserved

ISO/IEC 15438:2006(E)
Contents Page
Foreword. vi
Introduction . vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Symbols, operations and abbreviated terms. 3
4.1 Symbols . 3
4.2 Mathematical operations. 4
4.3 Abbreviated terms . 4
5 Requirements . 5
5.1 Symbology characteristics . 5
5.1.1 Basic characteristics. 5
5.1.2 Summary of additional features . 6
5.2 Symbol structure . 7
5.2.1 PDF417 symbol parameters. 7
5.2.2 Row parameters . 7
5.2.3 Codeword sequence. 7
5.3 Basic encodation . 8
5.3.1 Symbol character structure . 8
5.3.2 Start and stop characters . 9
5.4 High level (data) encodation. 10
5.4.1 Function codewords. 10
5.4.2 Text Compaction mode . 13
5.4.3 Byte Compaction mode. 17
5.4.4 Numeric Compaction mode . 19
5.4.5 Advice to select the appropriate compaction mode . 21
5.4.6 Treatment of PDF417 reserved codewords. 21
5.5 Extended Channel Interpretation . 21
5.5.1 Encoding the ECI assignment number. 22
5.5.2 Pre-assigned and default Extended Channel Interpretations . 23
5.5.3 Encoding ECI sequences within compaction modes . 23
5.5.4 Post-decode protocol. 25
5.6 Determining the codeword sequence.25
5.7 Error detection and correction . 26
5.7.1 Error correction level. 26
5.7.2 Error correction capacity . 26
5.7.3 Defining the error correction codewords.27
5.8 Dimensions. 27
5.8.1 Minimum width of a module (X). 27
5.8.2 Row height (Y). 28
5.8.3 Quiet zones. 28
5.9 Defining the symbol format . 28
5.9.1 Defining the aspect ratio of the module . 28
5.9.2 Defining the symbol matrix of rows and columns . 28
5.10 Generating the error correction codewords . 30
5.11 Low level encodation. 31
5.11.1 Clusters. 32
5.11.2 Determining the symbol matrix . 32
5.11.3 Determining the values of the left and right row indicators. 32
© ISO/IEC 2006 – All rights reserved iii

ISO/IEC 15438:2006(E)
5.11.4 Row encoding. 33
5.12 Compact PDF417. 33
5.13 Macro PDF417. 33
5.13.1 Compaction modes and Macro PDF417 . 34
5.13.2 ECIs and Macro PDF417 . 34
5.14 User guidelines . 34
5.14.1 Human readable interpretation. 34
5.14.2 Autodiscrimination capability. 34
5.14.3 User-defined application parameters. 34
5.14.4 PDF417 symbol quality. 35
5.15 Reference decode algorithm. 35
5.16 Error detection and error correction procedure . 35
5.17 Transmitted data . 35
5.17.1 Transmitted data in the basic (default) interpretation. 35
5.17.2 Transmission protocol for Extended Channel Interpretation (ECI) . 36
5.17.3 Transmitted data for Macro PDF417 . 37
5.17.4 Transmission of reserved codewords using the ECI protocol. 37
5.17.5 Symbology identifier. 37
5.17.6 Transmission using older protocols. 37
Annex A (normative) Encoding/decoding table of PDF417 symbol character bar-space sequences. 39
Annex B (normative) The default character set for Byte Compaction mode . 55
Annex C (normative) Byte Compaction mode encoding algorithm . 56
Annex D (normative) Numeric Compaction mode encoding algorithm. 58
Annex E (normative) User selection of error correction level . 60
E.1 Recommended minimum error correction level . 60
E.2 Other user consideration of the error correction level . 60
Annex F (normative) Tables of coefficients for calculating PDF417 error correction codewords . 61
Annex G (normative) Compact PDF417 . 66
G.1 Description. 66
G.2 Print quality. 66
Annex H (normative) Macro PDF417. 67
H.1 Macro PDF417 overview . 67
H.2 Macro PDF417 syntax . 67
H.3 High level encoding considerations . 70
H.4 Encodation example . 70
H.5 Macro PDF417 and the Extended Channel Interpretation protocol . 71
H.6 Macro PDF417 data transmission . 72
Annex I (normative) Testing PDF417 symbol quality. 75
Annex J (normative) Reference decode algorithm for PDF417 . 76
J.1 Initialisation . 76
J.2 Reference decode algorithm for line decoding. 76
J.3 Filling the matrix . 78
J.4 Interpretation . 79
Annex K (normative) Error correction procedures . 80
Annex L (normative) Symbology identifier . 82
Annex M (normative) Transmission protocol for decoders conforming with original PDF417
standards . 83
M.1 Basic Channel mode. 83
M.2 GLI encoded symbols. 83
M.3 Macro PDF417 symbols. 85
M.4 Transmission of reserved codewords using the original PDF417 protocol . 86
M.5 Achieving compatibility between old and new PDF417 equipment. 86
Annex N (informative) Algorithm to minimise the number of codewords . 89
iv © ISO/IEC 2006 – All rights reserved

ISO/IEC 15438:2006(E)
Annex O (informative) Guidelines to determine the symbol matrix. 91
O.1 Parameters affecting the determination of the matrix . 91
O.2 Guidelines should any parameters not be achieved. 94
Annex P (informative) Calculating the coefficients for generating the error correction codewords
– worked example. 95
Annex Q (informative) Generating the error correction codewords - worked example. 96
Annex R (informative) Division circuit procedure for generating error correction codewords. 99
Annex S (informative) Additional guidelines for the use of PDF417. 100
S.1 Autodiscrimination compatibility. 100
S.2 Pixel-based printing. 100
Bibliography . 102

© ISO/IEC 2006 – All rights reserved v

ISO/IEC 15438:2006(E)
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75 % of the national bodies casting a vote.
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.
ISO/IEC 15438 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 31, Automatic identification and data capture techniques.
This second edition cancels and replaces the first edition (ISO/IEC 15438:2001), which has been technically
revised.
vi © ISO/IEC 2006 – All rights reserved

ISO/IEC 15438:2006(E)
Introduction
The technology of bar coding is based on the recognition of patterns of bars and spaces of defined
dimensions. There are various methods of encoding information in bar code form, known as symbologies, and
the rules defining the translation of characters into bars and space patterns and other essential features are
known as the symbology specification.
Manufacturers of bar code equipment and users of bar code technology require publicly available standard
symbology specifications to which they can refer when developing equipment and application standards. It is
the intent and understanding of ISO/IEC that the symbology presented in this International Standard is entirely
in the public domain and free of all user restrictions, licences and fees.
© ISO/IEC 2006 – All rights reserved vii

INTERNATIONAL STANDARD ISO/IEC 15438:2006(E)

Information technology — Automatic identification and data
capture techniques — PDF417 bar code symbology
specification
1 Scope
This International Standard specifies the requirements for the bar code symbology known as PDF417. It
specifies PDF417 symbology characteristics, data character encodation, symbol formats, dimensions, error
correction rules, reference decoding algorithm, and a number of application parameters.
2 Normative references
The following referenced documents are indispensable for the application 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 646:1991, Information technology — ISO 7-bit coded character set for information interchange
ISO/IEC 8859-1, Information technology — 8-bit single-byte coded graphic character sets — Part 1: Latin
alphabet No. 1
ISO/IEC 15415, Information technology — Automatic identification and data capture techniques — Bar code
print quality test specification — Two-dimensional symbols
ISO/IEC 15424, Information technology — Automatic identification and data capture techniques — Data
Carrier Identifiers (including Symbology Identifiers)
ISO/IEC 19762-1, Information technology — Automatic identification and data capture (AIDC) techniques —
Harmonized vocabulary — Part 1: General terms relating to AIDC
ISO/IEC 19762-2, Information technology — Automatic identification and data capture (AIDC) techniques —
Part 2: Optically readable media (ORM)
ISO/IEC 24723, Information technology — Automatic identification and data capture techniques —
EAN.UCC Composite bar code symbology specification
AIM Inc. International Technical Standard: ITS/04-001, Extended Channel Interpretations —- Part 1:
Identification Schemes and Protocols

Published by AIM Global, 125 Warrendale-Bayne Road, Suite 100, Warrendale, PA 15086, USA.
© ISO/IEC 2006 – All rights reserved 1

ISO/IEC 15438:2006(E)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 19762-1, ISO/IEC 19762-2 and
the following apply.
3.1
basic channel model
standard system for encoding and transmitting bar code data where data message bytes are output from the
decoder but no control information about the message is transmitted
NOTE A decoder complying with this model operates in Basic Channel Mode.
3.2
bar-space sequence
sequence which represents the module widths of the elements of a symbol character
3.3
cluster
any of three mutually exclusive subsets of PDF417 symbol characters; the symbol characters in a given
cluster conform with particular structural rules which are used in decoding the symbology
3.4
compaction mode
any of three data compaction algorithms in PDF417 (Text, Numeric and Byte Compaction modes) which are
used to map 8-bit data bytes efficiently to PDF417 codewords
3.5
e-distance
distance from leading edge of an element to leading edge of the next similar element, or from trailing edge to
trailing edge
3.6
error correction codeword
codeword which encodes a value derived from the error correction codeword algorithm to enable decode
errors to be detected and, depending on the error correction level, to be corrected
3.7
Extended Channel Interpretation
ECI
procedure within some symbologies, including PDF417, to replace the default interpretation with another
interpretation in a reliable manner
NOTE The interpretation intended prior to producing the symbol can be retrieved after decoding the scanned symbol
to recreate the data message in its original format.
3.8
Extended Channel Model
system for encoding and transmitting both data message bytes and control information about the message,
the control information being communicated using Extended Channel Interpretation (ECI) escape sequences
NOTE A decoder complying with this model operates in Extended Channel Mode.
3.9
function codeword
codeword which initiates a particular operation within a symbology, for example to switch between data
encoding sets, to invoke a compaction scheme, to program the reader, or to invoke Extended Channel
Interpretations
2 © ISO/IEC 2006 – All rights reserved

ISO/IEC 15438:2006(E)
3.10
Global Label Identifier
GLI
procedure in the PDF417 symbology which behaves in a similar manner to Extended Channel Interpretation
NOTE The GLI system was the PDF417-specific precursor to the symbology-independent ECI system.
3.11
Macro PDF417
procedure in the PDF417 symbology logically to distribute data from a computer file across a number of
related PDF417 symbols
NOTE 1 The procedure considerably extends the data capacity beyond that of a single symbol.
NOTE 2 This procedure is similar to the Structured Append feature in other symbologies.
3.12
Mode Latch codeword
codeword which is used to switch from one mode to another mode, which stays in effect until another latch or
shift codeword is implicitly or explicitly brought into use, or until the end of the symbol is reached
3.13
Mode Shift codeword
codeword which is used to switch from one mode to another for one codeword, after which encoding returns
to the original mode
3.14
Row Indicator codeword
PDF417 codeword adjacent to the start or stop character in a row, which encodes information about the
structure of the PDF417 symbol in terms of the row identification, total number of rows and columns, and the
error correction level
3.15
Symbol Length Descriptor
first codeword in a PDF417 symbol, which encodes the total number of data codewords in the symbol
4 Symbols, operations and abbreviated terms
4.1 Symbols
For the purposes of this document, the following mathematical symbols apply. There are some cases where
the symbols below have been used in a different manner in an equation. This has been done for consistency
with a more general use of the notation and is always clearly defined in the text.
A symbol aspect ratio (height to width) of a PDF417 symbol
b element width in a symbol character
c number of columns in the symbol in the data region (excluding start, stop and row indicator
codewords)
d data codeword including all function codewords
E error correction codeword
e edge to similar edge dimension in a symbol character
F row number
© ISO/IEC 2006 – All rights reserved 3

ISO/IEC 15438:2006(E)
f number of substitution errors
H height of symbol including quiet zone
K cluster number
k number of error correction codewords
L left row indicator
l number of erasures
m number of source data codewords prior to the addition of the Symbol Length Descriptor and any pad
codewords
n total number of data codewords including Symbol Length Descriptor and any pad codewords
p pitch or width of a symbol character
Q horizontal quiet zone
H
Q vertical quiet zone
V
R right row indicator
r number of rows in the symbol
s error correction level
W width of symbol including quiet zone
X X-dimension or module width
Y module height (also called row height)
4.2 Mathematical operations
For the purposes of this document, the following mathematical operations apply.
div is the integer division operator, rounding down
INT is the integer value i.e. where a number is rounded down to its whole number component, ignoring
its decimal fractions
mod is the positive integer remainder after division. If the remainder is negative, add the value of the
divisor to make it positive. For example, the remainder of -29 160 divided by 929 is -361 which when
added to 929 yields 568.
4.3 Abbreviated terms
For the purposes of this document, the following abbreviated terms apply.
ECI Extended Channel Interpretation
GLI Global Label Identifier
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ISO/IEC 15438:2006(E)
5 Requirements
5.1 Symbology characteristics
5.1.1 Basic characteristics
PDF417 is a bar code symbology with the following basic characteristics:
a) Encodable character set:
1) Text Compaction mode (see 5.4.1.5) permits all printable ASCII characters to be encoded, i.e. values
32 - 126 inclusive in accordance with ISO/IEC 646 (IRV), as well as selected control characters.
2) Byte Compaction mode (see 5.4.3) permits all 256 possible 8-bit byte values to be encoded. This
includes all ASCII characters value 0 to 127 inclusive and provides for international character set
support.
3) Numeric Compaction mode (see 5.4.4) permits efficient encoding of numeric data strings.
4) Up to 811 800 different character sets or data interpretations.
5) Various function codewords for control purposes.
b) Symbol character structure: (n, k, m) characters of 17 modules (n), 4 bar and 4 space elements (k), with
the largest element 6 modules wide (m).
c) Maximum possible number of data characters per symbol (at error correction level 0): 925 data
codewords which can encode:
1) Text Compaction mode: 1 850 characters (at 2 data characters per codeword).
2) Byte Compaction mode: 1 108 characters (at 1,2 data characters per codeword).
3) Numeric Compaction mode: 2 710 characters (at 2,93 data characters per codeword)
At the minimum recommended error correction level, there is a maximum of 863 data codewords which
can encode:
4) Text Compaction mode: 1 726 characters (at 2 data characters per codeword).
5) Byte Compaction mode: 1 033 characters (at 1,2 data characters per codeword).
6) Numeric Compaction mode: 2 528 characters (at 2,93 data characters per codeword).
d) Symbol size:
1) Number of rows: 3 to 90.
2) Number of columns: 1 to 30.
3) Width in modules: 90X to 583X including quiet zones.
4) Maximum codeword capacity: 928 codewords.
5) Maximum data codeword capacity: 925 codewords.
Since the number of rows and the number of columns are selectable, the aspect ratio of a PDF417 symbol
may be varied when printing to suit the spatial requirements of the application.
© ISO/IEC 2006 – All rights reserved 5

ISO/IEC 15438:2006(E)
e) Selectable error correction: 2 to 512 codewords per symbol (see 5.7).
f) Non-data overhead:
1) Per row: 73 modules, including quiet zones.
2) Per symbol: a minimum of 3 codewords, represented as symbol characters.
g) Code type: continuous, multi-row two-dimensional.
h) Character self-checking: Yes.
i) Bi-directionally decodable: Yes.
5.1.2 Summary of additional features
Additional features which are inherent or optional in PDF417 are summarised below:
a) Data compaction: (inherent) Three schemes are defined to compact a number of data characters into
codewords. Generally data is not directly represented on a one character for one codeword basis (see
5.4.1.5 to 5.4.4).
b) Extended Channel Interpretations: (optional) These mechanisms allow up to 811 800 different data
character sets or interpretations to be encoded (see 5.5).
c) Macro PDF417: (optional) This mechanism allows files of data to be represented logically and
consecutively in a number of PDF417 symbols. Up to 99 999 different PDF417 symbols can be so linked
or concatenated and be scanned in any sequence to enable the original data file to be correctly
reconstructed (see 5.13).
d) Edge to edge decodable: (inherent) PDF417 can be decoded by measuring elements from edge to
similar edge (see 5.3.1).
e) Cross row scanning: (inherent) The combination of the following three characteristics in PDF417
facilitates cross row scanning:
⎯ being synchronised horizontally, or self clocking
⎯ row identification
⎯ being synchronised vertically, by using the cluster values to achieve local row discrimination.
This combination allows a single linear scan to cross a number of rows and achieve a partial decode of
the data so long as at least one complete symbol character per row is decoded into its codeword. The
decoding algorithm can then place the individual codewords into a meaningful matrix.
f) Error correction: (inherent) A user may define one of 9 error correction levels. All but Level 0 not only
detect errors but also can correct erroneously decoded or missing codewords (see 5.7).
g) Compact PDF417: (optional) In relatively ‘clean' environments, it is possible to reduce some of the row
overhead to improve the symbol density (see 5.12).
NOTE In earlier specifications of PDF417, Compact PDF417 was called Truncated PDF417. Compact PDF417 is
the preferred term to avoid confusion with the more general use of the term ‘truncated'.
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ISO/IEC 15438:2006(E)
5.2 Symbol structure
5.2.1 PDF417 symbol parameters
Each PDF417 symbol consists of a stack of vertically aligned rows with a minimum of 3 rows (maximum 90
rows). Each row shall include a minimum of 1 symbol character (maximum 30 symbol characters), excluding
start, stop and row indicator columns. The symbol shall include a quiet zone on all four sides. Figure 1
illustrates a PDF417 symbol encoding the text: PDF417 Symbology Standard.

Figure 1 — PDF417 symbol structure
5.2.2 Row parameters
Each PDF417 row shall comprise:
a) leading quiet zone
b) start character
c) left row indicator symbol character
d) 1 to 30 symbol characters
e) right row indicator symbol character
f) stop character
g) trailing quiet zone
NOTE The number of symbol characters (or codewords) defined in item ‘d' above is equal to the number of data
columns in the PDF417 symbol.
5.2.3 Codeword sequence
A PDF417 symbol may contain up to 928 symbol characters or codewords. Symbol character is the more
appropriate term to refer to the printed bar/space pattern; codeword is more appropriate for the numeric value
of the symbol character. The codewords shall follow this sequence:
a) The first codeword, the Symbol Length Descriptor, shall always encode the total number of data
codewords in the symbol, including the Symbol Length Descriptor itself, data codewords and pad
codewords, but excluding the number of error correction codewords.
b) The data codewords shall follow, from the most significant encodable character. Function codewords may
be inserted to achieve data compaction.
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ISO/IEC 15438:2006(E)
c) Pad codewords to enable the codeword sequence to be represented in a rectangular matrix. Pad
codewords may also be used to fill additional complete rows to achieve an aspect ratio desired or as
specified by the application.
d) An optional Macro PDF417 Control Block.
e) Error correction codewords for error detection and correction.
The codewords are arranged with the most significant codeword adjacent to the Symbol Length Descriptor,
and are encoded from left to right and from top row to bottom. Figure 2 illustrates in layout format the
sequence for a symbol like that shown in Figure 1. In Figure 2 an error correction level of 1 has been used
and one pad character was needed to completely fill the symbol matrix.
L d d R
1 15 14 1
L d d R
2 13 12 2
L d d R
3 11 10 3
S
L d d R
4 9 8 4
S
T
L d d R
T
5 7 6 5
A
L d d R O
6 5 4 6
R
P
L d d R
7 3 2 7
T
L d d R
8 1 0 8
L E E R
9 3 2 9
L E E R
10 1 0 10
Figure 2 — PDF417 Example of Symbol Layout Schematic
where L, R, d and E are as defined in clause 4
d  = Symbol Length Descriptor (in this example, with a value of 16)
d to d = encoded representation of data
14 1
d  = pad codeword
The rules and advice for structuring the matrix are included in 5.9.
5.3 Basic encodation
5.3.1 Symbol character structure
Each PDF417 symbol character shall consist of four bar elements and four space elements, each of which
can be one to six modules wide. The four bar and four space elements shall measure 17 modules in total.
PDF417 symbol characters can be decoded by measuring the e-distances within the character.
Each symbol character is defined by an 8-digit bar-space sequence which represents the module widths of the
eight elements of that symbol character. Figure 3 illustrates a symbol character with the bar-space sequence
51111125.
8 © ISO/IEC 2006 – All rights reserved

ISO/IEC 15438:2006(E)
Figure 3 — A PDF417 symbol character
There are 929 defined symbol character values (codewords) numbered from 0 to 928.
The codewords are represented by three mutually exclusive symbol character sets, or clusters. Each cluster
encodes the 929 available PDF417 codewords into different bar-space patterns so that one cluster is distinct
from another. The cluster numbers are 0, 3, and 6. The cluster definition applies to all PDF417 symbol
characters, except for start and stop characters.
The cluster number K is defined by the following formula:
K = (b - b + b - b + 9) mod 9
1 2 3 4
Where b , b , b and b represent the width in modules of the four bar elements respectively
1 2 3 4
The cluster number K for the symbol character in Figure 3 is:
K = (5 - 1 + 1 - 2 + 9) mod 9 = 3
The codewords and the bar-space sequences for each cluster of symbol characters are given in Annex A.
5.3.2 Start and stop characters
The start and stop characters shall be composed as defined in Table 1 and illustrated in Figure 4:
Table 1 — Bar-space sequence for Start and Stop Characters
Bar-space sequence
Character
B S B S B S B S B
Start 8 1 1 1 1 1 1 3
Stop 7 1 1 3 1 1 1 2 1
NOTE 1 The PDF417 stop and
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