Accessory

An accessory removably attachable to a camera body and including a plurality of terminals, the accessory comprising:

• a first terminal for causing the camera body to detect that the accessory is attached thereto;
• a second terminal through which a first power supply voltage is supplied from the camera body;
• a third terminal that is brought to a ground potential with respect to the first power supply voltage;
• a fourth terminal through which a second power supply voltage is supplied from the camera body;
• a fifth terminal that is brought to a ground potential with respect to the second power supply voltage;
• a sixth terminal used to indicate whether or not communication with the camera body is allowed;
• an eighth terminal that receives a first clock signal of a first cycle from the camera body;
• a seventh terminal that receives a first data signal in synchronization with the first clock signal from the camera body;
• a ninth terminal that outputs a third data signal to the camera body in synchronization with the first clock signal;
• a tenth terminal that outputs a second clock signal of a second cycle to the camera body, the second cycle being longer than the first cycle;
• and
• an eleventh terminal that outputs a second data signal to the camera body in synchronization with the second clock signal, wherein:
• the eighth terminal is positioned between the seventh terminal and the ninth terminal, and the tenth terminal is positioned between the ninth terminal and the eleventh terminal.