The DSE335 Automatic Transfer Switch Control Module has been expertly developed to monitor the voltage and frequency of an incoming AC supply from two different sources. These sources can be generator or mains (utility), or a combination of both. The control module monitors Source 1 (S1) and Source 2(S2). When a failure occurs a start command is issued to the inactive source to take over the load. The module will return the load to the mains (utility) as soon as this becomes available.