Emergency message boards have by now successfully become mainstream in culture and also familiar to many people. Message boards introducing emergency situation Amber alerts are perhaps one of the most commonplace (though such notices currently get to even more people with the temporary usurpation of their cellphones), however various other usages likewise are plentiful. These media appear over freeways to warn of delays or accidents, in sports stadia, in front of churches, and also at entries to high schools, upgrading their messages in real time. sync system clock