Code128条码规范中是否需要校验和? [英] Is a checksum required in the Code128 barcode specification?

问题描述

简介

步骤1

我尝试使用移动条形码阅读器和在线工具读取条形码(请参见下图)，并获得:数据- 30925018 ，可视化算法- Code128C

步骤2

然后我尝试根据给定的数据生成条形码并得到以下图像:

原始条形码

生成的条形码

步骤3

如您所见，图像是不同的.因此，我决定自己解密.结果如下:

原始解密的条形码

生成的解密条形码

С澄清

1. 如Wikipedia所述( https://en.wikipedia.org/wiki/Code_128 ):

   校验位是加权的103模校验和.通过将起始代码值"与每个符号值"的乘积乘以其在条形码字符串中的位置的乘积相加得出.

2. 我试图通过我的应用程序中的Java库以及在线工具根据给定的数据生成条形码.两者都给了我相同的结果.

问题

1. 为什么在线工具生成的条形码没有校验和，但末尾有FNC1?
2. 为什么条形码的开头有FNC1?
3. Code128规范是否要求校验和?

我的想法

• 我认为 GS1-128 规范可能是FNC1的起因条形码
最后的
• FNC1只能是校验和.只是巧合.

解决方案

原始图像是GS1-128(以前称为EAN-128)，代表以下GS1应用程序标识符格式的数据:

(30)925018

含义是项数:925018 .

• 我认为GS1-128规范可能是条形码开头的FNC1的原因

正确.根据定义，以FNC1字符开头的代码128是GS1-128，因此应包含根据GS1规范编码的数据.

以下答案中提供的背景描述了此编码背后的原理: https://stackoverflow.com/a/31760872/2568535

• 最后的FNC1只能是校验和.

在Code 128规范(和任何派生应用标准)中，校验和是必需的，并且通常不会以任何人类可读的文本形式显示.在您生成的符号中(不是GS1-128，因为没有"FNC1开头")，如果校验和字符恰好与FNC1匹配，那只是一个巧合，尽管-正如Brian Anderson所指出的-并非如此.

Introduction

Step 1

I tried to read the barcode (see image below) using a mobile barcode reader and online tools and got it: data - 30925018, visualization algorithm - Code128C

Step 2

Then I tried to generate a barcode from given data and got these images:

Original barcode

Generated barcode

Step 3

As you can see, the images are different. So, I decided to decrypt it by myself. Here is the result:

Original decrypted barcode

Generated decrypted barcode

Сlarifications

1. As Wikipedia says (https://en.wikipedia.org/wiki/Code_128):

   The check digit is a weighted modulo-103 checksum. It is calculated by summing the start code 'value' to the products of each symbol's 'value' multiplied by its position in the barcode string.

2. I tried to generate barcode from the given data by Java libs in my application, and by online tools. Both gave me the same result.

Questions

1. Why do online tools generate barcodes without a checksum, but with FNC1 at the end?
2. Why there is a FNC1 at the beginning of the barcode?
3. Is a checksum required by Code128 specification?

My thoughts

• I think GS1-128 specification can be cause of FNC1 at the beginning of the barcode
• FNC1 at the end can be just a checksum. It is just a coincidence.

解决方案

The original image is a GS1-128 (formerly EAN-128) representing the following GS1 Application Identifier formatted data:

(30)925018

The meaning is Count of items: 925018.

• I think GS1-128 specification can be cause of FNC1 at the beginning of the barcode

Correct. By definition a Code 128 beginning with an FNC1 character in first position is a GS1-128 and should therefore contain data encoded according to the GS1 specification.

The background provided in the following answer describes the principles behind this encoding: https://stackoverflow.com/a/31760872/2568535

• FNC1 at the end can be just a checksum.

The checksum is mandatory in the Code 128 specification (and any derivative application standards) and is not normally displayed in any human-readable text. In your generated symbol (not a GS1-128 since there is no "FNC1 in first") it would just be a coincidence if the checksum character happened to match FNC1, although - as noted by Brian Anderson - it doesn't.

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