Before revision: For a particular scenario of a use case, the diagrams show the events that external actors generate, their order, and possible inter-system events.System Sequence Diagrams ; the diagram places emphasis on events that cross the system boundary from actors to systems.
After revision: For a particular scenario of a use case, the diagrams show the events that external actors generate, their order, and possible inter-system events.System Sequence Diagrams The diagram emphasizes events that cross the system boundary from actors to systems.