Abstract: A control system is employed to selectively inhibit false signal transmissions between a communications processor and a plurality of peripheral devices during transient power states. The control system includes a comparator which detects a decrease in the unregulated power supply voltage as compared to the regulated voltage to anticipate an impending loss in regulated voltage. In response to a detected drop in unregulated voltage, a transistor interrupts the power supply to communications lines. Simultaneously, the transistor interrupts the power supply to a light source of an optically coupled relay which is employed to actuate a peripheral such as a mailing machine. In order to assure that the communications processor will initiallize after a transitory drop and a recovery in line voltage, a processor reset signal is also generated by the control system as a function of a detected decrease in unregulated voltage.