I’ve attached the extracted pages from the document which include chapter 6 (linear symbol rules) and chapter 10 (rules for bar code concatenation).
From the ICCBBA ISBT 128 Standard Technical Specification Chapter 10:
• the gap between last bar of the left bar code and the first bar of the right bar code shall be 36X ± 16X (That is equivalent to 9 ± 4 mm when the X dimension is 0.25 mm)
6 Delivery Mechanisms for ISBT 128
Data Structures
ISBT 128 data structures can be delivered using a number of different technologies including linear bar codes, two-dimensional (2-D) bar codes, wireless radio frequency identification transponders (RFID tags), and EDI messages. Rules for such uses of ISBT 128 data structures will depend on the delivery mechanism.
6.1 Linear Symbols
6.1.1 General Requirements
ISBT 128 data structures represented as linear bar codes shall use Code 128 symbology and be compliant with ISO/IEC 15417. Implementers shall ensure that a switch can be made to subset C of the Code 128 symbology where appropriate in order to reduce bar code length.
6.1.2 Symbol Print Quality
As described in ISO/IEC 15416, print quality of a Code 128 symbol shall be
1.5/6/670 where 1.5 is the overall quality, 6 is the measuring aperture reference number (corresponding to a 0.15 mm diameter aperture) and 670 is the peak
response wave length in nanometers. A 1.5 corresponds to a C grade in the
ANSI standard X3.182 – 1990.
6.1.3 Symbol Dimensions
Nominal module width (X): The X dimension shall be constant throughout a given symbol. The X dimension is the width of the narrowest bar within the bar code symbol.
Whenever possible, ISBT 128 bar codes used on a container label should be printed using a nominal X dimension of 0.25 mm, and in no case shall they be printed at a nominal X dimension smaller than 0.17 mm.
Note: Printers and scanners need to be compatible with the X dimension selected.
Any use of an ISBT 128 data structure as a linear printed bar code (i.e., not only on container labels, but on test tubes, etc.) should use an X dimension that meets these criteria.
Non-ICCBBA defined bar codes (such as national use bar codes) used on blood labels should meet the criteria listed above.
Bar Code Quiet Zones: The minimum width of a quiet zone shall be 10X.
A “quiet zone” is the clear space preceding the start character of the bar code and that following the stop character. This quiet zone is essential for the reading of the symbol.
There shall be no printing in direct contact with the top and bottom of the bar code.
Bar Code Height: In accordance with the recommendation in Annex G of ISO/IEC 15417, the bar code height shall be at least 5 mm or 15% of the symbol length, whichever is greater, on product labels that will leave the facility in which the products were labeled. For bar codes on labels or documents that will not leave the facility in which they were created, users should validate the minimum height of a label that can be read with their scanning equipment and ensure labels meet this internal requirement.
Concatenated Bar Codes: For linear bar codes that may be concatenated, the distance between the two bar codes shall fall within the specified range (see Chapter 10).
• the gap between last bar of the left bar code and the first bar of the right bar code shall be 36X ± 16X (That is equivalent to 9 ± 4 mm when the X dimension is 0.25 mm)
10 Bar Code Concatenation
This chapter provides the technical description of ISBT 128 concatenation for Code 128 symbols. It assumes an understanding of concatenation concepts and the basic differences between ISBT 128 concatenation and standard Code 128 concatenation. Additional background information can be obtained from the ICCBBA publications Technical Note 2, Length of the Product Code Bar Code and Concatenation and Technical Bulletin 5, Bar Code Scanner ISBT
128 Concatenation. These documents may be found on the ICCBBA Website.
10.1Temporal/Spatial Constraints
Temporal and/or spatial constraints shall be met before a pair of codes can be concatenated. The detailed requirements are:
• the gap between last bar of the left bar code and the first bar of the right bar code shall be 36X ± 16X (That is equivalent to 9 ± 4 mm when the X dimension is 0.25 mm)
• both bar codes shall be oriented in the same manner (the Standard allows flexibility to accommodate slight misalignment, but labels should be affixed so that the bars in
the bar codes are as close to parallel as possible)
• vertical alignment shall allow a single straight line scan to pass completely through both bar codes
• no vertical lines may appear between pairs of bar codes that are meant to be concatenated
• the stop codes shall be on the same side of both bar codes
Other variations of label design or placement shall not interfere with concatenation of paired bar codes (DIN and Blood Group; Product Code and Expiration Date and Time; and Container Manufacturer and Catalog Number and Container Lot Number).
In addition to these requirements, the X dimensions of both bar codes should be the same.
Note: The previous mandatory requirement for having the same X dimension for both bar codes was removed in version 3.0.0. However, recent evidence indicates this may cause problems. Until further evidence is available, we strongly recommend that the two bar codes be of the same X dimensions.
If any of the above constraints are not met the concatenation process shall be aborted. The scanner/decoder should immediately output the data of the correctly-read first bar code as if read without concatenation (this may be either bar code of the pair depending on the direction of scan). Reading and output of data from any other bar codes scanned then continues as an independent operation, as if a new scan had been started.
The techniques recommended to scanner manufacturers to ensure that the spatial separation constraint is applied are detailed in Technical Bulletin 5.
No maximum length for a pair of bar codes for concatenation is defined. However, the maximum length of a code pair that can be read will be determined by the scanner design.
10.2Output Data String
ISBT 128 concatenation shall result in a single output data string containing the data from the left bar code followed by the data from the right bar code, regardless of the order of scanning. The terms left and right bar code are defined such that the stop code of the left bar code is adjacent to the start code of the right bar code.
The output data string shall contain all data characters in each bar code, including the data identifiers, in left-to-right byte order (i.e., starting with the left primary data identifier) regardless of the direction in which the bar codes are scanned. Internal Code 128
control characters, such as start, stop, and subset shift are non-data characters and thus do not appear in the output string.
10.3Controlling the Concatenation Process
At any point in the bar code data entry process one of the following concatenation requirements shall apply:
a) concatenated read required;
concatenated read prohibited;
c) concatenated read permitted but not required.
Enforcement of these requirements may be carried out either by the host application software or by programming the scanner.
Where control is carried out by the application software, the scanner shall be configured to allow both single and ISBT 128 concatenated reads. The application software can then apply the required control (a, b, or c) for each scanning transaction.
Alternatively, scanners that support internal control of ISBT 128 concatenation mode may be programmed to allow ISBT 128 concatenation mode configuration, allowing the scanner to be set to operate according to a, b, or c above. Requirements a and b are referred to as static modes, and when configured to one of these the scanner will enforce the requirement every time an ISBT 128 bar code is scanned. If the scanner is configured to dynamic mode, c, then both single and concatenated reads are allowed.
10.4Verification of Valid Concatenation
The above rules ensure that a concatenated read occurs only when required. This section is concerned with verifying the pair of bar codes once they have been received.
The ISBT 128 concatenation methodology allows the concatenation of any pair of ISBT
128 bar codes; however, in general, only a limited set of bar code pairs will be concatenated. Once again, control over this verification can be carried out either by the host application software or by the scanner software.
Using application software control, the application may be written to accept only the expected concatenated pair at each input event. The scanner in this situation shall be configured to pass through any pair of valid ISBT 128 bar codes.
Alternatively, the scanner may be configured to allow only specific pairs of bar codes to be accepted. Where such control is used it is essential that the scanner configuration permit the table of acceptable bar code pairs to be modified and extended. A Concatenation Programming Bar Code has been provided as an ISBT 128 data structure to support the management of acceptable pairs. Detailed consideration of this process is provided in Technical Bulletin 5.
10.5Commonly Concatenated Bar Code Pairs
The following is a list of bar code pairs that are commonly concatenated. The list is not exhaustive and the Standard allows any pair of ISBT 128 codes to be concatenated. Reference to the corresponding data structure is given in parentheses.
• Donation Identification Number [001] and Blood Groups [ABO and RhD] [002]
• Product Code [003] and Expiration Date and Time [005]
• Donation Identification Number [001] and Product Code [003]
• Donation Identification Number [001] and Donor Identification Number [019]
• Container Manufacturer and Catalog Number [017] and Container Lot Number [018]
• Manufacturer and Catalog Number: Items Other Than Containers [021] and Lot
Number: Items Other Than Containers [022]
• Patient Birth Date [024] and Patient Identification Number [025]
It is possible to concatenate other pairs of ISBT 128 bar codes and these can be specified within some scanner systems (see Technical Bulletin 5).
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