CCITT Rec. Q.83.2 (1988) – CALL COMPLETION SUPPLEMENTARY SERVICES – CALL HOLD
2 Call hold
2.1 Introduction
2.1.1 Definition
2.2 Definition of functional model
2.2.1 Functional model description
2.2.2 Relationship to basic service
2.3 Information flow description
2.3.1 Information flow diagram for successful operation
2.3.2 Definition of individual information flows
2.4 Functional entity actions
2.5 SDL diagrams for functional entities
2.6 Network physical allocation scenarios