title This is a title participant UserA participant A participant B participant UserB #UserA<-A: CCCH Paging UserA->A: CCCH Connection request A->UserA: CCCH Connection setup UserA->A: DCCH Connection setup complete UserA->A: DCCH Security mode command UserA<-A: DCCH Security mode command complete space UserA->A: REQUEST UserA->A: SETUP UserA<-A: CALL PROCEEDING #A->B: ISUP IAM UserA<-A: FACILITY UserA<-A: PROGRESS B<-UserB: CCCH Paging B<-UserB: CCCH Connection request B->UserB: CCCH Connection setup UserB->B: DCCH Connection setup complete UserB->B: DCCH Security mode command UserB<-B: DCCH Security mode command complete space UserB<-B: SETUP UserB->B: CALL CONFIRM UserB->B: ALERTING # B->A:ISUP IAC UserA<-A: ALERTING UserB->B: CONNECT #B->A: ISUP ANSWER A->UserA: CONNECT UserA->A: CONNECT ACK B->UserB: CONNECT ACK UserA->A: DISCONNECT #A->B: ISUP Release A->UserA: Release UserA->A: Release complete B->UserB: Disconnect UserB->B: Release #B->A: ISUP Release Complete B->UserB: Release Complete