Patent ID: 6973582

Claim:
An information processor including a digital signal output terminal, said information processor comprising: optical signal generation means; drive means for controlling said optical signal generation means based on received digital signals; detection means for detecting whether or not a plug is connected to said digital signal output terminal; and power supply cutoff means for cutting off the power supply to said drive means when said detection means has detected that a plug is not connected to said digital signal output terminal, wherein said power supply cutoff means comprises: a PNP transistor including a base that receives a connection detection signal that indicates whether or not a plug is connected to said digital signal output terminal and an emitter that is connected to a high-level voltage; a pull-up resistor for pulling up said connection detection signal to a high-level voltage; and an n-channel MOS transistor including a gate connected to the collector of said PNP transistor, a drain connected to a power supply voltage, and a source connected to the power supply input terminal of said drive means.