This is an open CIA (USA in Australia) telephone number . They are attempting to get a "sound print" for the purposes of analysing any sounds recorded to see if there are "elements" !!! , present at that number and address . They usually know quite well who they are calling . The reason it hangs up immediately is the diagnostic machine needs only a fraction of a moment to record enough sound to create a diagnostic . The fake sellers assist them (knowingly ?) by obtaining replies from the called individual which supplies a voice print for that person .
This number is to BE AVOIDED !! . Best policy is to immediately hang up , and then start screaming at the walls for 2 minutes . May throw them off !!.