本标准提供了ATM适配层的一部分功能，用于支持B-ISDN网络节点接口（NNI）处的信令（SAAL）。该功能用于将AAL的特定于服务的面向连接协议（SSCOP）的服务映射到ATIS-1000111中定义的NNI SAAL用户的需求。这些要求涵盖了网络节点和网络之间的信令需求。该功能称为NNI信令服务规范协调功能（SSCF）。以前称为T1。645-1995（R2008）。

This standard provides a function that is part of the ATM Adaptation Layer for the support of signaling (SAAL) at the Network Node Interface (NNI) of the B-ISDN. This function is used to map the service of the Service Specific Connection Oriented Protocol (SSCOP) of the AAL to the requirements of an SAAL user at the NNI as defined in ATIS-1000111. These requirements cover the needs for signaling between network nodes and networks. This function is called Service Specification Coordination Function (SSCF) for signaling at the NNI. Formerly known as T1.645-1995(R2008).