User A
User B
Answer message (ANM)
LE A
LE B
TE
User B answers
User B answers, connection is cut through at LE B.
Charging of the call starts when ANM message is received at LE A.
Conversation can take place over the bi-directional circuit switched
connection.
Charging starts now
Conversation over this “pipe”
Signalling
sequence 4 (call setup)