Printing apparatus

An apparatus including a control unit which controls a device including a sensor, and a cable which connects the device and the control unit, comprising:

• a first signal line and a second signal line configured to be respectively laid out on the cable and to be connected to the sensor, wherein a voltage occurred between the first signal line and the second signal line corresponds to a state of the device;
• a differential amplifier circuit configured to be included in the control unit, amplify the voltage occurred between the first signal line and the second signal line, and output the amplified voltage as state information of the device;
• and
• an adjusting circuit configured to adjust a wiring resistance of the first signal line and a wiring resistance of the second signal line by connecting one of the first signal line and the second signal line via a resistor to a power supply line of the device, wherein
• the sensor is a npn transistor,
• the first signal line connects an emitter terminal of the npn transistor and an input terminal of the differential amplifier circuit,
• the second signal line connects a base terminal of the npn transistor and another input terminal of the differential amplifier circuit, and
• the resistor is connected between a collector terminal of the npn transistor and the base terminal, wherein the collector terminal is connected to the power supply line of the device.