ETSI PRI-ETS 300 319-1995 综合业务数字网(ISDN);1号数字用户信号系统(DSS1);电路模式基本呼叫的信号网络层协议的部分协议实施附加测试信息(PIXIT)形式规范
Integrated Services Digital Network (ISDN); Digital Subscriber Signalling System No. One (DSS1) Partial Protocol Implementation eXtra Information for Testing (PIXIT) Proforma Specification for Signalling Network Layer Protocol for Circuit-Mode Basic Call