An interface to connect sensor equipment and a physiological monitor includes a first connector to receive power from a first channel of the monitor and a second connector to receive power from a second channel of the monitor. The power from each of the first and second channels of the monitor is combined within the interface. The interface further includes a third connector to provide the combined power to the sensor equipment; a voltage converter to rescale the voltage of the combined power that is provided to the sensor equipment; and a scaling circuit to reduce the voltage of a signal representing a measured physiological parameter. The signal representing the measured physiological parameter is sent from the sensor equipment to the monitor. The interface is advantageous to allow sensor equipment to be sufficiently powered by a monitor that would not typically provide enough power.