At 2:00PM today, Australia will conduct a nationwide test of its new "OzAlert" emergency system, broadcasting a loud 10-second siren and full-screen warning to mobile phones - even those set to silent, missing SIM cards, or disconnected from primary carrier networks.

Tech Guide editor Stephen Fenech joined Jason Matthews on 4BC Breakfast to break down how cell broadcast technology powers this warning system, emphasising crucial instructions for hidden safety phones to switch to airplane mode while explaining why older handsets might fail the test.