Information technology -- Automatic identification and data capture techniques -- PDF417 bar code symbology specification

ISO/IEC 15438:2015 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.

Technologies de l'information -- Techniques automatiques d'identification et de capture des données -- Spécifications pour la symbologie de code à barres PDF417

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Status
Published
Publication Date
13-Sep-2015
Current Stage
9020 - International Standard under periodical review
Start Date
15-Jul-2020
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INTERNATIONAL ISO/IEC
STANDARD 15438
Third edition
2015-09-15
Information technology — Automatic
identification and data capture
techniques — PDF417 bar code
symbology specification
Technologies de l’information — Techniques automatiques
d’identification et de capture des données — Spécifications pour la
symbologie de code à barres PDF417
Reference number
ISO/IEC 15438:2015(E)
ISO/IEC 2015
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ISO/IEC 15438:2015(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2015, Published in Switzerland

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ii © ISO/IEC 2015 – All rights reserved
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ISO/IEC 15438:2015(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols, operations and abbreviated terms .......................................................................................................................... 3

4.1 Symbols ......................................................................................................................................................................................................... 3

4.2 Mathematical operations ............................................................................................................................................................... 4

4.3 Abbreviated terms ............................................................................................................................................................................... 4

5 Requirements .......................................................................................................................................................................................................... 4

5.1 Symbology characteristics ............................................................................................................................................................ 4

5.1.1 Basic characteristics ..................................................................................................................................................... 4

5.1.2 Summary of additional features ......................................................................................................................... 5

5.2 Symbol structure ................................................................................................................................................................................... 6

5.2.1 PDF417 symbol parameters .................................................................................................................................. 6

5.2.2 Row parameters ............................................................................................................................................................... 6

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 ....................................................................................................................................................... 9

5.4.1 Function codewords ..................................................................................................................................................10

5.4.2 Text Compaction mode ............................................................................................................................................12

5.4.3 Byte Compaction mode ...........................................................................................................................................17

5.4.4 Numeric Compaction mode .................................................................................................................................19

5.4.5 Advice to select the appropriate compaction mode .......................................................................20

5.4.6 Treatment of PDF417 reserved codewords...........................................................................................20

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 ................................................22

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 ..............................................................................................................................................25

5.7.1 Error correction level ...............................................................................................................................................25

5.7.2 Error correction capacity ......................................................................................................................................26

5.7.3 Defining the error correction codewords................................................................................................26

5.8 Dimensions ..............................................................................................................................................................................................27

5.8.1 Minimum width of a module (X) .....................................................................................................................27

5.8.2 Row height (Y) ................................................................................................................................................................27

5.8.3 Quiet zones ........................................................................................................................................................................27

5.9 Defining the symbol format ......................................................................................................................................................27

5.9.1 Defining the aspect ratio of the module ....................................................................................................27

5.9.2 Defining the symbol matrix of rows and columns ...........................................................................28

5.10 Generating the error correction codewords ...............................................................................................................29

5.11 Low level encodation ......................................................................................................................................................................30

5.11.1 Clusters .................................................................................................................................................................................31

5.11.2 Determining the symbol matrix .......................................................................................................................31

5.11.3 Determining the values of the left and right row indicators ...................................................32

5.11.4 Row encoding ..................................................................................................................................................................32

5.12 Compact PDF417 ................................................................................................................................................................................32

5.13 Macro PDF417 ......................................................................................................................................................................................32

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ISO/IEC 15438:2015(E)

5.13.1 Compaction modes and Macro PDF417 ....................................................................................................33

5.13.2 ECIs and Macro PDF417 .........................................................................................................................................33

5.14 User guidelines ....................................................................................................................................................................................33

5.14.1 Human readable interpretation .......................................................................................................................33

5.14.2 Autodiscrimination capability ...........................................................................................................................33

5.14.3 User-defined application parameters .........................................................................................................33

5.14.4 PDF417 symbol quality ...........................................................................................................................................34

5.15 Reference decode algorithm.....................................................................................................................................................34

5.16 Error detection and error correction procedure ....................................................................................................34

5.17 Transmitted data ................................................................................................................................................................................34

5.17.1 Transmitted data in the basic (default) interpretation ...............................................................34

5.17.2 Transmission protocol for Extended Channel Interpretation (ECI) .................................35

5.17.3 Transmitted data for Macro PDF417 ...........................................................................................................36

5.17.4 Transmission of reserved codewords using the ECI protocol ...............................................36

5.17.5 Symbology identifier .................................................................................................................................................36

5.17.6 Transmission using older protocols .............................................................................................................36

Annex A (normative) Encoding/decoding table of PDF417 symbol character bar-

space sequences .................................................................................................................................................................................................37

Annex B (normative) The default character set for Byte Compaction mode ...........................................................60

Annex C (normative) Byte Compaction mode encoding algorithm ...................................................................................61

Annex D (normative) Numeric Compaction mode encoding algorithm .......................................................................63

Annex E (normative) User selection of error correction level ................................................................................................65

Annex F (normative) Tables of coefficients for calculating PDF417 error correction codewords ...66

Annex G (normative) Compact PDF417 ..........................................................................................................................................................70

Annex H (normative) Macro PDF417 ................................................................................................................................................................71

Annex I (normative) Testing PDF417 symbol quality ......................................................................................................................79

Annex J (normative) Reference decode algorithm for PDF417 .............................................................................................80

Annex K (normative) Error correction procedures ...........................................................................................................................84

Annex L (normative) Symbology identifier ................................................................................................................................................86

Annex M (normative) Transmission protocol for decoders conforming with original

PDF417 standards ............................................................................................................................................................................................87

Annex N (informative) Algorithm to minimise the number of codewords ................................................................93

Annex O (informative) Guidelines to determine the symbol matrix ................................................................................95

Annex P (informative) Calculating the coefficients for generating the error correction

codewords – worked example .............................................................................................................................................................99

Annex Q (informative) Generating the error correction codewords - worked example ..........................100

Annex R (informative) Division circuit procedure for generating error correction codewords .....104

Annex S (informative) Additional guidelines for the use of PDF417 ...........................................................................106

Bibliography .........................................................................................................................................................................................................................108

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ISO/IEC 15438:2015(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.

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 meaning of ISO specific terms and expressions related to conformity

assessment, as well as information about ISO’s adherence to the WTO principles in the Technical

Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information

The committee responsible for this document is ISO/IEC JTC 1, Information technology, Subcommittee

SC 31, Automatic identification and data capture techniques.

This third edition cancels and replaces the second edition (ISO/IEC 15438:2006), of which it constitutes

a minor revision.
© ISO/IEC 2015 – All rights reserved v
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ISO/IEC 15438:2015(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.

vi © ISO/IEC 2015 – All rights reserved
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INTERNATIONAL STANDARD ISO/IEC 15438:2015(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 documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. 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, Information technology — ISO 7-bit coded character set for information interchange

ISO/IEC 15415, Information technology — Automatic identification and data capture techniques — Bar

code symbol 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 — Harmonized vocabulary — Part 2: Optically readable media (ORM)

ISO/IEC 24723, Information technology — Automatic identification and data capture techniques — GS1

Composite bar code symbology specification
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 1 to entry: 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

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ISO/IEC 15438:2015(E)
3.3
cluster
any of the three mutually exclusive subsets of PDF417 symbol characters

Note 1 to entry: 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 the 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 the leading edge of an element to the leading edge of the next similar element, or from

trailing edge to trailing edge
3.6
error correction codeword

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 1 to entry: 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 1 to entry: A decoder complying with this model operates in Extended Channel Mode.

3.9
function codeword
initiates a particular operation within a symbology

EXAMPLE To switch between data encoding sets, to invoke a compaction scheme, to program the reader, or

to invoke Extended Channel Interpretations.
3.10
Global Label Identifier
GLI

procedure in the PDF417 symbology which behaves in a similar manner to Extended Channel

Interpretation

Note 1 to entry: 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 to entry: The procedure considerably extends the data capacity beyond that of a single symbol.

Note 2 to entry: This procedure is similar to the Structured Append feature in other symbologies.

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ISO/IEC 15438:2015(E)
3.12
Mode Latch codeword

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

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 International Standard, 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 code-

words)
d data codeword including all function codewords
E error correction codeword
e edge to similar edge dimension in a symbol character
F row number
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

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ISO/IEC 15438:2015(E)
p pitch or width of a symbol character
Q horizontal quiet zone
Q vertical quiet zone
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 International Standard, 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 International Standard, the following abbreviated terms apply.

ECI Extended Channel Interpretation
GLI Global Label Identifier
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 to 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;

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ISO/IEC 15438:2015(E)
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.

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 minim
...

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