本文件规定了程序和协议要求，以支持在客户场所和网络内的两个互通功能之间，通过基于ATM的接入部分高效地提供PSTN和ISDN服务。该规范将基于ATM论坛规范STR-VMOA-LES-01.00（ATM上的语音和多媒体-使用AAL2的环路仿真服务），并对选项进行适当选择或限制，如有必要，进行修改和修订。

This document specifies the procedural and protocol requirements to support the efficient delivery of PSTN and ISDN services across an ATM based access section between two Interworking Functions located at the customer premises and within the network, respectively. The specification will be based on the ATM Forum specification STR-VMOA-LES-01.00 (Voice and Multimedia over ATM - Loop Emulation Service using AAL2), with appropriate selection or restriction of options and, if necessary, modifications and amendments.