SHOW_DURATION_ON_DISCONNECT defines if the duration of completed call is displayed to user.
If SHOW_DURATION_ON_DISCONNECT is 1, then user will see something like: "Call with 12345 completed. Duration is 0:33"
If SHOW_DURATION_ON_DISCONNECT is 1, then user will see only: "Call with 12345 completed"
Example:
!define SHOW_DURATION_ON_DISCONNECT 1