ETSI PRETS 300 171-1991 Specification, Functional Model and Information Flows for Control Aspects of Circuit Mode Basic Services in Private Telecommunications Networks
1992ETSI PRETS 300 171-1992 Private Telecommunications Network (PTN); Specification, Functional Model and Information Flows Control Aspects of Circuit Mode Basic Services
1991ETSI PRETS 300 171-1991 Specification, Functional Model and Information Flows for Control Aspects of Circuit Mode Basic Services in Private Telecommunications Networks