本标准定义了综合业务数字网（ISDN）数字用户信号系统1号（DSS1）中原因信息元素的用法、格式和编码。它还定义了特定原因的含义，以及位置和诊断字段的用法。以前称为T1。650-1995（R2005）。

This standard defines the usage, format, and encoding of the cause information element within the context of the Digital Subscriber Signaling System Number 1 (DSS1) of an Integrated Services Digital Network (ISDN). It also defines the meaning of specific causes, and the usage of the location and diagnostic fields. Formerly known as T1.650-1995(R2005).