The present disclosure provides a signal convertor, which includes a circuit board, a plurality of isolation transformers, a capacitor, a signal-converting module, an electrical connection interface and a plugging interface. The isolation transformers, the capacitor, the signal-converting module are disposed on the circuit board. The signal-converting module is for converting a plugging signal received from the plugging interface into an electrical signal and transferring the electrical signal to the isolation transformers, or for converting the electrical signal received from the isolation transformers into the plugging signal and transferring the plugging signal to the plugging interface.