Information technology -- Automatic identification and data capture techniques -- Interleaved 2 of 5 bar code symbology specification

ISO/IEC 16390:2007 specifies the requirements for the bar code symbology known as Interleaved 2 of 5; it specifies Interleaved 2 of 5 symbology characteristics, data character encodation, dimensions, tolerances, decoding algorithms and parameters to be defined by applications. It specifies the Symbology Identifier prefix strings for Interleaved 2 of 5 symbols.

Technologies de l'information -- Techniques automatiques d'identification et de capture des données -- Spécifications des symbologies des codes à barres, code 2 parmi 5 entrelacé

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Published
Publication Date
11-Jun-2007
Current Stage
9093 - International Standard confirmed
Start Date
23-Apr-2020
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INTERNATIONAL ISO/IEC
STANDARD 16390
Second edition
2007-06-15
Information technology — Automatic
identification and data capture
techniques — Interleaved 2 of 5 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 2 parmi 5 entrelacé
Reference number
ISO/IEC 16390:2007(E)
ISO/IEC 2007
---------------------- Page: 1 ----------------------
ISO/IEC 16390:2007(E)
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© ISO/IEC 2007

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

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ii © ISO/IEC 2007 – All rights reserved
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ISO/IEC 16390:2007(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.............................................................................................................................................5

4.5 Reference decode algorithm ................................................................................................................6

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 Interleaved 2 of 5 .............................................................11

Annex C (normative) Symbology identifier ....................................................................................................14

Annex D (informative) Examples of application-defined parameters ..........................................................15

Bibliography ......................................................................................................................................................17

© ISO/IEC 2007 – All rights reserved iii
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ISO/IEC 16390:2007(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 16390 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 16390:1999), which has been technically

revised.
iv © ISO/IEC 2007 – All rights reserved
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ISO/IEC 16390:2007(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.

Interleaved 2 of 5 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 16390:2007(E)
Information technology — Automatic identification and data
capture techniques — Interleaved 2 of 5 bar code symbology
specification
1 Scope

This International Standard specifies the requirements for the bar code symbology known as Interleaved 2 of

5; it specifies Interleaved 2 of 5 symbology characteristics, data character encodation, dimensions, tolerances,

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

strings for Interleaved 2 of 5 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 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 Interleaved 2 of 5 are:

a) Encodable character set: numeric 0 to 9 (ASCII characters 48 - 57 inclusive, in accordance with

ISO/IEC 646);
b) Code type: continuous;
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ISO/IEC 16390:2007(E)

c) Elements per symbol character: 5, of which 2 wide and 3 narrow, encoded as either five bars or five

spaces;
d) Character self-checking: yes;
e) Data string length encodable: variable (even number of digits);
f) Bidirectionally decodable: yes;
g) Symbol check character: one, optional (see annex A);

h) Symbol character density: 14 to 18 modules per symbol character pair, depending on wide/narrow ratio;

i) Non-data overhead: 8 to 9 modules, depending on wide/narrow ratio.
4.2 Symbol structure
Interleaved 2 of 5 symbols shall comprise:
a) leading quiet zone;
b) start pattern;

c) one or more pairs of symbol characters representing data (inclusive of optional symbol check character);

d) stop pattern;
e) trailing quiet zone.
4.3 Character encodation
4.3.1 Symbol character structure

Data is encoded as interleaved pairs of symbol characters, the first of which comprises two wide and three

narrow bars and the second of which comprises two wide and three narrow spaces, the first bar of the first

character being followed by the first space of the second character, then the second bar of the first character

and the second space of the second character, and so on until the last space of the second character, which

is directly followed by the first bar of the next symbol character pair (or stop pattern).

4.3.2 Data character encodation

Table 1 defines the Interleaved 2 of 5 character encodation. In the columns headed "Binary representation"

the character 1 is used to represent a wide element and 0 a narrow element.
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ISO/IEC 16390:2007(E)
Table 1 — Binary representation of character encodation
Data character Binary representation
0 0 0 1 1 0
1 1 0 0 0 1
2 0 1 0 0 1
3 1 1 0 0 0
4 0 0 1 0 1
5 1 0 1 0 0
6 0 1 1 0 0
7 0 0 0 1 1
8 1 0 0 1 0
9 0 1 0 1 0

Table 1 uses a modified binary coded decimal encoding scheme. The four left-most bit positions for each

character are assigned weights of 1, 2, 4 and 7, from left to right; the fifth position is used for an even parity

bit. The sum of the positional weights of the '1' bits is equivalent to the data character value, except in the

case of the data character 0, where the weights 4 and 7 are applied. The parity bit ensures that there are

always two '1' bits per character.

The following algorithm defines the rules to convert numeric data into the symbol characters of an Interleaved

2 of 5 symbol:
Step in Algorithm Example
367
1) Calculate check character if required by the application standard. See 4.7;
0367
2) If the data string, including check characters, has an odd number of digits,
add a leading zero;
which becomes
0367
3) Subdivide the numeric string into digit pairs;
03 and 67
which becomes
4) Encode each digit pair in turn as follows:
a) Encode the leading digit of the pair into a pattern of bars as shown in
(binary pattern 00110)
Table 1;
b) Encode the second digit of the pair into a pattern of spaces as shown in
(binary pattern 11000)
Table 1;
Binary pattern
5) Form each symbol character pair by taking the bar and space elements
0101101000
alternately from the patterns derived from steps 4 a) and 4 b), commencing

with the first bar of the pattern for the first digit, followed by the first space of

the pattern for the second digit.

Figure 1 illustrates the sequence of bar and space elements corresponding to the data character pairs

"03 67".
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ISO/IEC 16390:2007(E)
NEXT CHAR.
Figure 1 — Interleaved 2 of 5 character pairs, encoding "03 67"
4.3.3 Start and stop patterns

The start pattern shall consist of four narrow elements in the sequence bar - space - bar - space. The stop

pattern shall consist of a wide bar - narrow space - narrow bar sequence.

The start pattern shall be positioned at the normal left end of the data symbol characters adjacent to the first

bar of the most significant digit. The stop pattern shall be positioned at the normal right end of the data symbol

characters adjacent to the final space of the least significant digit.

There is no assigned human readable interpretation of the start and stop patterns and they shall not be

transmitted by the decoder.

Figure 2 illustrates the start and stop patterns and their relationship to the symbol data characters.

Quiet zone Quiet zone
First char. Last char.
START STOP
Figure 2 — Start and stop patterns
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ISO/IEC 16390:2007(E)

Figure 3 illustrates a complete Interleaved 2 of 5 bar code symbol for the data "1234" showing the necessary

quiet zones.
Quiet zone Start 1st character pair 2nd character pair Stop Quiet zone
1234
Figure 3 — Interleaved 2 of 5 symbol inclusive of quiet zones
4.3.4 Optional symbol check character
Annex A defines the check character position and calculation.
4.4 Dimensions
Interleaved 2 of 5 symbols shall use the following nominal dimensions:

⎯ width of narrow element (X): the X dimension of Interleaved 2 of 5 symbols should be defined by the

application specification in accordance with the needs of the application in question. See 4.7.1;

⎯ wide/narrow ratio (N): 2,0:1 to 3,0:1;
⎯ minimum width of quiet zone: 10X;

⎯ recommended minimum bar code height for manual scanning: 5,0 mm or 15 % of symbol width excluding

quiet zones, whichever is greater.

The width, W (in millimetres) of an Interleaved 2 of 5 symbol, including quiet zones, can be calculated from the

following expression:
W=[P(4N+ 6)+ N+ 6]X+ 2Q
where:
W is the symbol width;
P is the number of symbol character pairs;
N is the wide/narrow ratio;
X is the width of a narrow element in millimetres;
Q is the width of the quiet zone in millimetres.
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ISO/IEC 16390:2007(E)
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.
1) Confirm presence of a leading quiet zone.

2) Confirm presence of a valid start pattern by checking that the widths of the initial four elements are

each less than 7/64 the sum of the next ten elements (if this fails, reverse decoding may be

attempted).

3) Decode the exact number of character pairs specified by the application as follows:

(1) Record the widths of the ten elements of a character pair and accumulate their sum, S;

(2) Compute a threshold, T = (7 / 64)S;

(3) Compare the individual widths with the threshold: if element width is greater than T,

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

4) Verify that in each group of five bars and five spaces two bar and two space elements are wide and

three bar and three space are narrow.

5) Using Table 1, convert the wide and narrow pattern of the five bars and five spaces respectively into

the first and second digits of the digit pair.

6) After decoding the proper number of character pairs, confirm the presence of a valid stop pattern by

checking that the next element width is greater than or equal to the T of the previous symbol

character and that the widths of the following two elements widths are less than T.

7) Confirm the presence of a trailing quiet zone.
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 subclause 4.5 of

this specification 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 nanometers.

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.
NOTE Certain application specifications may define a decode a
...

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