Dial out state.
Normal process: Calling-> Ringing->Accepted->Success
Busy process: Calling->Busy
User accepted the call.
Busy.
Calling.
Failed to cancel the call.
Canceled the call.
Canceling the call.
Call failed.
User hung up the call.
Service unavailable.
Ringing.
Call succeeded.
Timeout.
Dial out state.
Normal process: Calling-> Ringing->Accepted->Success
Busy process: Calling->Busy