Integrated Services Digital Network (ISDN); Digital Subscriber Signalling System No. one (DSS1) protocol; Generic functional protocol for the support of supplementary services at the b service entry point for Virtual Private Network (VPN) applications; Part 4: Abstract Test Suite (ATS) and partial P
综合业务数字网(ISDN);数字用户信令系统第一号(DSS1)协议;在虚拟专用网(VPN)应用的b服务入口点支持补充服务的通用功能协议;第4部分:抽象测试套件(ATS)和部分P