In any emergency, backup must arrive in time and intact; and in data centers, ABB digital static transfer switches help ensure that emergency power comes on line so fast and so reliably that the changeover is invisible. ABB’s Cyberex unit invented the DSTS 30 years ago. Now ABB has advanced DSTS use in data centers to monitor power quality, anticipate impending problems and switch to an alternative power source so effectively that the DSTS enables 99.9999 percent uptime. Christopher Belcastro and Hans Pfitzer lay out ABB’s approach to building redundancy into data centers by deploying digital static transfer switches.