Information technology -- Automatic identification and data capture techniques -- Code 39 bar code symbology specification

The technology of bar coding is based on the recognition of patterns encoded in bars and spaces of defined dimensions. There are numerous methods of encoding information in bar code form, known as symbologies. Code 39 is one such symbology. The rules defining the translation of characters into bar and space patterns and other essential features are known as the symbology specification. In the past, symbology specifications were developed and published by a number of organizations, resulting in certain instances in conflicting requirements for certain symbologies. 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. ISO/IEC 16388:2007 specifies the requirements for the bar code symbology known as Code 39; it specifies Code 39 symbology characteristics, data character encodation, dimensions, tolerances, decoding algorithms and parameters to be defined by applications. It specifies the Symbology Identifier prefix strings for Code 39 symbols.

Technologies de l'information -- Techniques automatiques d'identification et de capture des données -- Spécifications des symbologies des codes à barres, code 39

General Information

Status
Published
Publication Date
08-May-2007
Current Stage
6060 - International Standard published
Start Date
25-Apr-2007
Completion Date
09-May-2007
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INTERNATIONAL ISO/IEC
STANDARD 16388
Second edition
2007-05-15
Information technology — Automatic
identification and data capture
techniques — Code 39 bar code
symbology specification
Technologies de l'information — Techniques d'identification
automatique et de capture des données — Spécifications des
symbologies des codes à barres, code 39
Reference number
ISO/IEC 16388:2007(E)
ISO/IEC 2007
---------------------- Page: 1 ----------------------
ISO/IEC 16388:2007(E)
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© ISO/IEC 2007

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ii © ISO/IEC 2007 – All rights reserved
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ISO/IEC 16388:2007(E)
Contents Page

Foreword............................................................................................................................................................ iv

Introduction ........................................................................................................................................................ v

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

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

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

4 Requirements ........................................................................................................................................ 1

4.1 Symbology characteristics .................................................................................................................. 1

4.2 Symbol structure .................................................................................................................................. 2

4.3 Character encodation........................................................................................................................... 2

4.4 Dimensions............................................................................................................................................ 4

4.5 Reference decode algorithm ............................................................................................................... 5

4.6 Symbol quality ...................................................................................................................................... 6

4.7 Application-defined parameters.......................................................................................................... 7

Annex A (informative) Additional features....................................................................................................... 9

Annex B (informative) Guidelines for the use of Code 39............................................................................ 12

Annex C (normative) Symbology identifier ................................................................................................... 15

Annex D (informative) Example of application-defined parameters ........................................................... 16

Bibliography ..................................................................................................................................................... 18

© ISO/IEC 2007 – All rights reserved iii
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ISO/IEC 16388:2007(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 16388 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 16388:1999), which has been technically

revised.
iv © ISO/IEC 2007 – All rights reserved
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ISO/IEC 16388:2007(E)
Introduction

The technology of bar coding is based on the recognition of patterns encoded in bars and spaces of defined

dimensions. There are numerous methods of encoding information in bar code form, known as symbologies.

Code 39 is one such symbology. The rules defining the translation of characters into bar and space patterns

and other essential features are known as the symbology specification.

In the past, symbology specifications were developed and published by a number of organizations, resulting in

certain instances in conflicting requirements for certain symbologies.

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.

© ISO/IEC 2007 – All rights reserved v
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INTERNATIONAL STANDARD ISO/IEC 16388:2007(E)
Information technology — Automatic identification and data
capture techniques — Code 39 bar code symbology
specification
1 Scope

This International Standard specifies the requirements for the bar code symbology known as Code 39; it

specifies Code 39 symbology characteristics, data character encodation, dimensions, tolerances, decoding

algorithms and parameters to be defined by applications. It specifies the Symbology Identifier prefix strings for

Code 39 symbols.
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, Information technology — ISO 7-bit coded character set for information interchange

ISO/IEC 15416, Information technology — Automatic identification and data capture techniques — Bar code

print quality test specification — Linear 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)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO/IEC 19762-1 and ISO/IEC 19762-2

apply.
4 Requirements
4.1 Symbology characteristics
The characteristics of Code 39 are as follows.
a) Encodable character set:

1) full alphanumeric A to Z and 0 to 9 (ASCII characters 65 to 90 and 48 to 57 inclusive, in accordance

with ISO 646).
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ISO/IEC 16388:2007(E)

2) special characters: space $ % + - . / (ASCII characters 32, 36, 37, 43, 45, 46 and 47, respectively, in

accordance with ISO 646).
3) start/stop character.
b) Code type: discrete.

c) Elements per symbol character: 9, of which 3 wide and 6 narrow, comprising 5 bars and 4 spaces.

d) Character self-checking: yes.
e) Data string length encodable: variable.
f) Bidirectionally decodable: yes.
g) Symbol check character: one, optional (see Annex A).

h) Symbol character density: 13 to 16 modules per symbol character, inclusive of minimum intercharacter

gap, depending on wide/narrow ratio.
i) Non-data overhead: equivalent to 2 symbol characters.
4.2 Symbol structure
As illustrated in Figure 1, Code 39 symbols shall comprise
a) leading quiet zone;
b) start character;

c) one or more symbol characters representing data (including symbol check character, if present);

d) stop character;
e) trailing quiet zone.
A space, the intercharacter gap, shall separate characters within the symbol.
QUIET ZONE START CHARACTER "1" "A" STOP CHARACTER QUIET ZONE
Figure 1 — Code 39 symbol
4.3 Character encodation
4.3.1 Symbol character structure

Each symbol character comprises nine elements (five bars and four spaces) of which six are always narrow

(either three narrow bars and three narrow spaces, or five narrow bars and one narrow space) and three are

always wide (one wide space and two wide bars when there are three narrow bars, or three wide spaces

when there are five narrow bars). This parity feature enables character self-checking to be carried out.

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ISO/IEC 16388:2007(E)
4.3.2 Symbol character assignments
Table 1 defines all the Code 39 character assignments.
Table 1 — Code 39 character assignments
ASCII
Char. Encodation Pattern BSBSBSBS B
value
0 0 001 10 10 0 48
1 1 001 00 00 1 49
2 0 011 00 00 1 50
3 1 011 00 00 0 51
4 0 001 10 00 1 52
5 1 001 10 00 0 53
6 0 011 10 00 0 54
7 0 001 00 10 1 55
8 1 001 00 10 0 56
9 0 011 00 10 0 57
A 1 000 01 00 1 65
B 0 010 01 00 1 66
C 1 010 01 00 0 67
D 0 000 11 00 1 68
E 1 000 11 00 0 69
F 0 010 11 00 0 70
G 0 000 01 10 1 71
H 1 000 01 10 0 72
I 0 010 01 10 0 73
J 0 000 11 10 0 74
K 1 000 00 01 1 75
L 0 010 00 01 1 76
M 1 010 00 01 0 77
N 0 000 10 01 1 78
O 1 000 10 01 0 79
P 0 010 10 01 0 80
Q 0 000 00 11 1 81
R 1 000 00 11 0 82
S 0 010 00 11 0 83
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ISO/IEC 16388:2007(E)
ASCII
Char. Encodation Pattern BSBSBSBSB
value
T 0 000 10 110 84
U 1 100 00 001 85
V 0 110 00 001 86
W 1 110 00 000 87
X 0 100 10 001 88
Y 1 100 10 000 89
Z 0 110 10 000 90
hyphen 0 100 00 101 45
period 1 100 00 100 46
space 0 110 00 100 32
$ 0 101 01 000 36
/ 0 101 00 010 47
+ 0 100 01 010 43
% 0 001 01 010 37
S/S or 0 100 10 100 none
NOTE 1 S/S denotes the start and stop character, usually graphically represented
as *
NOTE 2 In the columns headed B and S, 0 represents a narrow element and 1 a
wide element.
4.3.3 Start and stop characters

The Code 39 start and stop character is usually depicted in human-readable form by a * (asterisk). This

character shall not form part of the data encoded elsewhere in the symbol and shall not be transmitted by the

decoder.

The start character shall be positioned at the normal left end of the data symbol characters, separated from

the first bar of the leading data character by an intercharacter gap. The stop character shall be positioned at

the normal right end of the data symbol characters (including symbol check character if present), separated

from the final bar of the trailing data character by an intercharacter gap.
4.3.4 Optional symbol check character
Annex A defines the symbol check character position and calculation.
4.4 Dimensions
Code 39 symbology shall use the following nominal dimensions.

a) Width of narrow element (X): the X dimension of Code 39 symbols should be defined by the application

specification having due regard to the availability of equipment for the production and reading of symbols

and complying with the general requirements of the application. See 4.7.1.
b) Wide/narrow ratio (N): 2,0 : 1 to 3,0 : 1.
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ISO/IEC 16388:2007(E)
c) Width of intercharacter gap (I):
1) minimum: equal to X;
2) maximum:
for X < 0,287 mm: 5,3X;
for X ≥ 0,287 mm: 1,52 mm or 3X, whichever is greater.
d) Minimum width of quiet zone: 10X.

e) Recommended minimum bar code height for manual scanning: 5,0 mm or 15 % of symbol width

excluding quiet zones, whichever is greater.

NOTE The width, W (in millimetres), of a Code 39 symbol, including quiet zones, can be calculated from the following

expression:
WC=+23N+6X+C+1I+2Q
()( ) ( )
where
W is the symbol width;
C is the number of data characters (including symbol check character if used);
N is the wide/narrow ratio;
X is the width of a narrow element in millimetres;
l is the width of the intercharacter gap in millimetres;
Q is the width of the quiet zone in millimetres.
4.5 Reference decode algorithm

Bar code reading systems are designed to read imperfect symbols to the extent that practical algorithms

permit. This section describes the reference decode algorithm used in the computation of the decodability

value described in ISO/IEC 15416.
a) Confirm presence of a leading quiet zone.
b) For each symbol character (including start and stop characters):
1) Measure the total width of 5 bars and 4 spaces; call this S.
2) Compute a threshold value, T = S / 8.

3) Compare each element width for that character with the value T. If element width is greater than T,

assume element is wide; if not, assume element is narrow.

4) Determine if pattern of wide and narrow elements matches a valid character from the allowable set.

c) The first symbol character read must be a start/stop character, from which the scan direction can be

deduced.
d) Continue character reading until a valid start/stop character is encountered.
e) Confirm presence of a trailing quiet zone.
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ISO/IEC 16388:2007(E)
4.6 Symbol quality
4.6.1 Test specification

In order to verify whether a symbol meets the specifications in this International Standard it shall be tested

using the test specification defined in ISO/IEC 15416, which defines a standardized methodology for

measuring and grading bar code symbols, as supplemented in 4.6.2. ISO/IEC 15416 lays down conditions

under which measurements should be made; and defines methods of determining an overall quality grade

based on the attributes of the bar code symbol. The reference decode algorithm defined in 4.5 shall be used

for the assessment of the "decode" and "decodability" parameters under ISO/IEC 15416.

The overall symbol grade shall be expressed in the form shown in the following example:

1,5 / 10 / 660
where
1,5 is the overall symbol quality grade;

10 is the measuring aperture reference number (in this example 0,25 mm diameter);

660 is the peak response wavelength in nanometres.

ISO/IEC 15416 allows for additional pass/fail criteria to be stipulated by a symbology specification. For

Code 39, the additional criteria are given in 4.6.2. Any individual scan profile which does not meet these

requirements shall receive a grade of 0.
4.6.2 Additional parameters
4.6.2.1 Wide/narrow ratio

Symbols shall be produced with a nominal N from 2,0 to 3,0 inclusive. The measured value of N in any scan

profile shall be in the range 1,8 to 3,4 inclusive. The wide/narrow ratio in the scan reflectance profile under

ISO/IEC 15416 shall be measured and graded as follows.
1,8 ≤ N ≤ 3,4: Grade 4.
N < 1,8 or N > 3,4: Grade 0.
4.6.2.2 Intercharacter gap

For symbols with a measured narrow element width (Z) less than 0,287 mm, the maximum allowed

intercharacter gap is 5,3Z. For symbols with Z greater than or equal to 0,287 mm, the maximum intercharacter

gap is the greater of 3Z or 1,52 mm. Each intercharacter gap in the scan reflectance profile under

ISO/IEC 15416 shall be measured and graded as follows.
I ≤ G : Grade 4.
max
I < G : Grade 0.
max
where
G = 5,3Z for Z < 0,287 mm or G = MAX(1,52 mm, 3Z) for Z ≥ 0,287 mm
max max
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ISO/IEC 16388:2007(E)
4.6.2.3 Quiet zone

The quiet zone at each end of the symbol shall be a minimum of 10Z. Both left and right quiet zones on each

scan reflectance profile under ISO/IEC 15416 shall be measured and graded as follows.

Quiet Zone ≥ 10Z: Grade 4.
Quiet Zone < 10Z: Grade 0.

NOTE In 4.6.2.1 to 4.6.2.3, the requirements are based on the actual, rather than intended, measurements of the

parameter; for this r
...

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