destination is not available...

[nashakhalov]

If calling to a mobile phone that is switched off users hear: destination is not available not registered or no route available. Is there any option to hear GSM carrier message instead?

 

[leejor]

That probably depends on whether you are going out over a VoIP provider or a gateway and where the recording that you hear is originating. If you are using a VoIP provider and they get a certain message back from the mobile company then that is the recording that they provide to the caller.