综合业务数字网（ISDN）用户部分定义了支持在综合业务数字网中提供语音和非语音服务所需的信令功能的协议。本标准基于ITU-T研究组11于2000年发布的《国际使用7号信令系统规范》及其后续修订版。本标准以ITU的国际指定ISDN用户部分为基础，并在适用的情况下使用相同的信令程序、参数和消息类型- T信号系统7号。PTSC-IOP工作组制定了本标准，以满足美国网络内部和网络之间的预期需求和应用。

The Integrated Services Digital Network (ISDN) User Part defines the protocol which supports the signaling functions required to provide voice and non-voice services in an Integrated Services Digital Network. This standard is based on the Specification of Signaling System No. 7 for international use issued by ITU-T Study Group 11 in the year 2000 and subsequent amendments. This standard is based on and uses, where applicable, the same signaling procedures, parameters, and message types as the internationally specified ISDN User Part of the ITU-T Signaling System No.7. Working group PTSC-IOP has developed this standard to suit anticipated needs and application within and between U.S. networks.