I don’t understand why you don’t think there should be a new conn id after the transfer is complete.
Here’s a log generated by a tlib utility I wrote showing a transfer from DN 21106 to DN 21107 of a call placed by DN 21112 to DN 21106:
21106 presses transfer, 2112 is put on hold:
9/12/2006 3:15:52 PM: EventHeld, Conn ID:0078015eb530e83d, This DN:21106, Other DN:21112
Pressing transfer involves selecting a new line, this is where the new conn id comes in. 21106 now has 2 conn id’s associated with it:
9/12/2006 3:15:52 PM: EventOffHook, Conn ID:0078015eb530e83e, This DN:21106, Other DN:
9/12/2006 3:15:52 PM: EventOffHook, Conn ID:0078015eb530e83e, This DN:21106, Other DN:
21106 dials 21107 and they connect:
9/12/2006 3:15:55 PM: EventDialing, Conn ID:0078015eb530e83e, This DN:21106, Other DN:21107
9/12/2006 3:15:55 PM: EventRinging, Conn ID:0078015eb530e83e, This DN:21107, Other DN:21106
9/12/2006 3:15:55 PM: EventRinging,0078015eb530e83e,21107,21106,21106,21107,
9/12/2006 3:15:56 PM: EventEstablished, Conn ID:0078015eb530e83e, This DN:21107, Other DN:21106
9/12/2006 3:15:56 PM: EventEstablished, Conn ID:0078015eb530e83e, This DN:21106, Other DN:21107
21106 completes the transfer, and now 21112 is talking to 21107:
9/12/2006 3:15:57 PM: EventReleased, Conn ID:0078015eb530e83d, This DN:21106, Other DN:21112
9/12/2006 3:15:57 PM: EventReleased, Conn ID:0078015eb530e83e, This DN:21106, Other DN:21107
9/12/2006 3:15:57 PM: EventOnHook, Conn ID:0000000000000000, This DN:21106, Other DN:
9/12/2006 3:15:57 PM: EventOnHook, Conn ID:0000000000000000, This DN:21106, Other DN:
21107 and 21112 are notified by EventPartyChanged that 21106 has left the new conn id:
9/12/2006 3:15:57 PM: EventPartyChanged, Conn ID:0078015eb530e83d, This DN:21112, Other DN:21107
9/12/2006 3:15:57 PM: EventPartyChanged, Conn ID:0078015eb530e83d, This DN:21107, Other DN:21112
Hope that answers your questions.