A powered device includes a first switch, a second switch, and a controller. The first switch is disposed between a center tap of the first transformer and a center tap of the third transformer. The second switch is disposed between a center tap of the second transformer and a center tap of the fourth transformer. The controller is coupled to the first switch and the second switch. The controller is constructed and arranged to output a control signal to the first and second switches to electrically connect the center taps of the first and third transformers together and concurrently electrically connect the center taps of the second and fourth transformers together. The powered device is constructed and arranged to operate in 4-pair mode when the center taps of the first and third transformers are connected together and the center taps of the second and fourth transformers are connected together.