
Private Telecommunication Network (Ptn) - Specification, Functional Model And Information Flows - Call Intrusion Supplementary Service
出版:Polish Committee for Standardization

專家解讀視頻
Private Telecommunication Network (Ptn) - Specification, Functional Model And Information Flows - Call Intrusion Supplementary Service
出版:Polish Committee for Standardization
專家解讀視頻