Patent ID: 8762606

Claim:
A signal processing apparatus comprising: a signal processor which processes a data signal; a power supply which generates a power signal; a first connector configured to be connected with an external second connector; and a control circuit which outputs the data signal and the power signal if the external second connector is connected to the first connector, and performs a shutoff operation to not output the power signal if the first connector is not connected to the external second connector; wherein the first connector comprises a plurality of pins, including a power pin, and the control circuit performs the shutoff operation by not outputting the power signal to the power pin of the first connector; and wherein the control circuit comprises: a switching unit which comprises an enabling pin; and a resistor which connects the power pin of the first connector with the enabling pin of the switching unit; wherein the switching unit receives the power signal at the enabling pin and selectively outputs the power signal to the first connector based on a voltage level of the enabling pin, and wherein the switching unit outputs the power signal to the first connector when the external second connector of a first external device having a first impedance is connected to the first connector, and does not output the power signal to the first connector when the external second connector of a second external device having a second impedance that is lower than the first impedance is connected to the first connector.