Transfer

Step	API	Action/Result	Event
1		<---	GCEV_OFFERED(CRN 1)
2	gc_AnswerCall( ) (CRN 1)	--->
3	gc_HoldCall( ) (CRN 1)	--->
4		<---	GCEV_HOLDACK(CRN 1)
5	gc_MakeCall( )	--->
6		<---	GCEV_PROCEEDING(CRN 2 with Inquiry IE)
7		<---	GCEV_CONNECTED(CRN 2 with Inquiry IE)
8	gc_SndMsg( ) (SndMsg_Transfer, CRN 1)	--->
9	gc_SndMsg( ) (SndMsg_Transfer, CRN 2)	--->
10			GCEV_TRANSFERACK(CRN 1)
11			GCEV_TRANSFERACK(CRN 2)
12	Cross connect CRN 1's and CRN 2's SCbus time slots
13		<---	GCEV_TRANSIT(CRN 1)
14	gc_SndMsg( ) (SndMsg_Transit, CRN 2)	--->
15		<---	GCEV_TRANSIT(CRN 2)
16	gc_SndMsg( ) (SndMsg_Transit, CRN 1)	--->
17		<---	GCEV_DISCONNECT(CRN 1)
18	gc_DropCall( ) (CRN 1)	--->
19		<---	GCEV_DROPCALL(CRN 1)
20	gc_ReleaseCall( ) (CRN 1)	--->
21		<---	GCEV_DISCONNECT(CRN 2)
22	gc_DropCall( ) (CRN 2)	--->
23		<---	GCEV_DROPCALL(CRN 2)
24	gc_ReleaseCall( ) (CRN 2)	--->

The procedure is as follows:

1. Party 2 receives an incoming call (GCEV_OFFERED) event from Party 1.
2. Party 2 answers call from Party 1 using the gc_AnswerCall( ) function.
3. Party 2 places the call on hold using the gc_HoldCall( ) function.
4. Some switches may not support holding a call.
5. Party 2 receives a call on hold acknowledge (GCEV_HOLDACK) event.
6. Party 2 places an inquiry call to Party 3 using the gc_MakeCall( ) function. The application should use Party 1's telephone number as the calling party number and Party 3's telephone number as called party number. See Table 70, Inquiry IE for the Inquiry IE format.
7. Party 2 receives a call proceeding (GCEV_PROCEEDING) event with an Inquiry IE from Party 3. See Table 70, Inquiry IE for the Inquiry IE format.
8. Party 2 receives a call connected (GCEV_CONNECTED) event with Inquiry IE from Party 3. See Table 70, Inquiry IE for the Inquiry IE format.
9. Party 2 sends a transfer request to Party 1 with a TRANSFER_ORIG value as the transfer direction using the gc_SndMsg( ) function. See Table 78, SndMsg_Transfer for the message format.
10. Party 2 sends a transfer request to Party 3 with a TRANSFER_TERM value as the transfer direction using the gc_SndMsg( ) function. See Table 78, SndMsg_Transfer for the message format.
11. Party 2 receives a transfer acknowledge (GCEV_TRANSFERACK) event from Party 1.
12. Party 2 receives a transfer acknowledge (GCEV_TRANSFERACK) event from Party 3. Transfer completed. At this time, Party 2 loses control of the call.
13. The application should cause Party 1 to listen to Party 2's SCbus transmit time slot and Party 2 to listen to Party 1's SCbus transmit time slot.
14. Party 2 receives a transit (GCEV_TRANSIT) event from Party 1. Party 2 should retrieve the content of the Transit IE using the gc_GetSigInfo( ) function.
15. Party 2 sends content of the Transit IE (unchanged) from Party 1 to Party 3 using the gc_SndMsg( ) function. See Table 79, SndMsg_Transit for the message format.
16. Party 2 receives a transit (GCEV_TRANSIT) event from Party 3. Party 2 should retrieve the content of the Transit IE using the gc_GetSigInfo( ) function.
17. Party 2 sends content of Transit IE (unchanged) from Party 3 to Party 1 using the gc_SndMsg( ) function. See Table 79, SndMsg_Transit for the message format.
18. Party 2 receives a disconnect all (GCEV_DISCONNECT) event from Party 1.
19. Party 2 drops the call to Party 1 using the gc_DropCall( ) function.
20. Party 2 receives a drop call (GCEV_DROPCALL) event from Party 1.
21. Party 2 releases the call to Party 1 using the gc_ReleaseCall( ) function.
22. Party 2 receives a disconnect call (GCEV_DISCONNECTED) event from Party 3.
23. Party 2 drops the call to Party 3 using the gc_DropCall( ) function.
24. Party 2 receives a drop call (GCEV_DROPCALL) event from Party 3.
25. Party 2 releases call to Party 3 using the gc_ReleaseCall( ) function.

Notes:

1. Steps 3 and 4 are optional and need not be carried out on most PBXs.
2. Steps 12 through 16 may be repeated multiple times depending on when or whether the distant PBX supports Route Optimization. When Route Optimization occurs, or if either end of the transferred call is terminated, the call flow proceeds to step 17.

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