I hardly think holding the microphone close to your smartphone is going to pass a 'safety case' for a function like this. In any case you've got to find someone who owns a smartphone with the app.
Sabenaboy, you don't seem to realise that anything ATC related has to be an approved system allowable under national aviation authority regulations.
As others have said, normal ATSUs do not have access to Selcal, just oceanic ones, so whilst laudable, your idea is a non-starter.
Last edited by chevvron; 23rd Apr 2016 at 07:54.