ITU-T Rec. X.724 (1993) ISO/IEC 10165-6:1994 defines a standard method for specifying the agent and message conformance in a manager-agent Operations System (OS) interaction that uses OSI systems management-based messages. This revision extends ITU-T Rec. X.724 ISO/IEC 10165-6 to cover the manager end of the interaction. The result of this extension is that the time to carry out interoperability tests between a manager OS from one vendor and an agent OS from another vendor may be reduced because product developers can be provided with more explicit message specification for the manager OS.