需要识别读卡器在自动识别环境中检测到的数据载体。符号标识符概念为从读取器接收数据的设备提供了一种标准化的方式，以区分数据载体。ISO/IEC 15424:2008主要涉及条形码符号；因此，术语符号标识符、符号和条形码在ISO/IEC 15424:2008中使用，尽管它们也适用于其他数据载体。 这种识别是通过向读卡器添加可选功能来实现的，该功能使读卡器能够为数据消息添加标准字符串前缀。 该前导包含关于解码符号（或其他数据载体）和读取器所做的任何处理的信息。信息没有被编码或以其他方式显式或隐式地表示在符号中，除非某些可选特征的存在可能被读取设备检测到，而其他一些特征则要求对读取器进行明确配置以实现它们。 ISO/IEC 15424:2008应与相关符号规范一起阅读。 ISO/IEC 15424:2008适用于自动识别设备通信约定，并对条形码阅读器和其他自动识别设备的数据载体报告进行了标准化。 它指定由读取器生成并可由接收系统解释的前导消息，该消息指示条形码符号或传输数据的其他来源，以及与数据消息相关的特定可选处理特征的细节。

The need exists to identify the data carrier a reader detects in autodiscrimination environments. The Symbology Identifier concept provides a standardized way for a device receiving data from a reader to differentiate between the data carriers. ISO/IEC 15424:2008 deals mostly with bar code symbologies; the terms Symbology Identifier, symbology, and bar code are therefore used throughout ISO/IEC 15424:2008 although they are intended to apply to other data carriers as well. This identification is achieved by the addition of an optional feature to readers enabling the reader to prefix a standard string of characters to data messages. This preamble contains information about the decoded symbol (or other data carrier) and any processing the reader has done. The information is not encoded or otherwise explicitly or implicitly represented in the symbol, except that the presence of some optional features may be detected by the reading equipment, whereas others require the reader to be expressly configured to implement them. ISO/IEC 15424:2008 should be read in conjunction with the relevant symbology specifications. ISO/IEC 15424:2008 applies to automatic identification device communication conventions and standardizes the reporting of data carriers from bar code readers and other automatic identification equipment. It specifies a preamble message generated by the reader and interpretable by the receiving system, which indicates the bar code symbology or other origin of transmitted data, together with details of certain specified optional processing features associated with the data message.