SS7 - ISUP Answer Message (22/Q.763 (09/97))
A message sent in the backward direction indicating that the call has been answered. In semi-automatic working, this message has a supervisory function. In automatic working, this message is used in conjunction with charging
information in order to:
- start metering the charge to the calling subscriber (see Recommendation Q.28 [2]); and
- start measurement of call duration for international accounting purposes (see Recommendation E.260 [3]).
NOTE 1 - This parameter may be repeated.
NOTE 2 - Peer-to-peer interworking with an earlier version of ISUP may result in format errors and lead to the release of the call.