Determination circuit

A determination circuit comprising:

• a first detecting unit configured to detect whether first and second power-supply terminals are connected to each other, based on a voltage at the second power-supply terminal of a coupling unit, the coupling unit including:
• the second power-supply terminal connectable to the first power-supply terminal of a device including the first power-supply terminal applied with a power-supply voltage and first and second terminals, and
• third and fourth terminals connectable respectively to the first and the second terminals having impedance corresponding to a type of the device, after the first power-supply terminal and the second power-supply terminal are connected to each other;
• a voltage applying unit configured to, when the first and the second power-supply terminals are connected to each other, apply a first voltage to the third terminal as well as apply a second voltage to the fourth terminal;
• a second detecting unit configured to detect that the first and the second terminals are connected to the third and the fourth terminals, respectively, when a voltage level at the third terminal is not equal to a level of the first voltage or when a voltage level at the fourth terminal is not equal to a level of the second voltage, after the second voltage is applied to the fourth terminal while the first voltage is applied to the third terminal;
• and
• a discrimination unit configured to discriminate a type of the device based on voltages at the third and the fourth terminals when it is detected that the first and the second terminals are connected to the third and the fourth terminals, respectively.