Micro-controller and electro-mechanical based logic; easily replaceable window legends; wide input voltage range (18-88 V DC and 88-350 V AC/DC); standard modules - 1, 2, 6, 8, 11, 15, 19, 23 and any custom built system; fascia windows with long life super bright LEDs; all site selection by DIP switch at the rear (back) side of the unit; flashing synchronisation in group annunciation; and various operating sequences selectable at site.