An information handling system includes a system board configured to serialize sideband signals from a sideband cable resulting in serialized sideband signals, and a peripheral device expansion card that has a power management embedded controller. If the sideband cable is connected to the peripheral device expansion card, then the controller may transmit the sideband signals to a card controller. If the sideband cable is not connected to the peripheral device expansion card, then the controller may decode and parallelize the serialized sideband signals resulting in parallelized sideband signals, and transmit the parallelized sideband signals to the controller. The controller determines a power state of the information handling system based on the sideband signals from the sideband cable or the parallelized sideband signals.