The present disclosure relates to a polarity correction circuit. The polarity correction circuit may include a detection module and a switching module. The detection module may be configured to detect a polarity of a DC voltage transmitted to a powered device and generate one or more control signals based on the polarity of the DC voltage. The switching module may be configured to receive the one or more control signals and a data signal transmitted from the powered device. The switching module may be further configured to adapt a polarity of the data signal based on the one or more control signals such that the polarity of the data signal is accordant with the polarity of the DC voltage.