2001ECMA 142-2001 Private Integrated Services Network (PISN) - Circuit Mode 64kbit/s Bearer Services - Service Description, Functional Capabilities and Information Flows (3rd Edition)
1997ECMA 142-1997 Private Integrated Services Network (PISN) - Circuit Mode 64kbit/s Bearer Services - Service Description@ Functional Capabilities and Information Flows (BCSD) (2nd Edition)
1990ECMA 142-1990 Specification@ Functional Model and Information Flows for Control Aspects of Circuit Mode Basic Services in Private Telecommunication Networks