An algorithm for verifying the state of switches (such as in a transfer switch mechanism) and for controlling the switches. The control algorithm controls automatic actuation of the switches. The verification algorithm measures the instantaneous voltage on the source and load sides of one or both switches and calculates the RMS magnitude, period, and relative phase for each voltage measurement. If the voltage characteristics for the load do not match any of those for any source, an error is outputted. If the voltage characteristics of the sources match each other, the algorithm determines that they are synchronized. The algorithm determines which switch is closed by comparing the voltage characteristics of the load and of each source, and if there is a match, then the switch associated with the source that is matched with the load is determined to be closed. Otherwise, the switch is determined to be opened.