Anns 3 : The announcement played between ACM and REL.
There will be RELEASE CAUSE in ISUP-REL Which may explain why the call released.
Means it may relate somehow to the EVENT whcih relaesed the call.
REL May be sent from either direction depending upon Release Event.
As per my observation :-
No Response ANNOUNCEMENT – A Exchange Releases.
Detached Mode ANNS – B Exchange Releases.
Messages : IAM–>