Electronic apparatus and accessory

An accessory detachably attached to an electronic apparatus via an accessory shoe, the accessory comprising a plurality of contacts electrically connectable to the accessory shoe of the electronic apparatus and arranged in a first direction orthogonal to a direction in which the accessory is attached to the electronic apparatus,

• wherein the plurality of contacts include:
• a first signal contact used to transmit a data signal in a communication between the electronic apparatus and the accessory;
• a second signal contact used to receive a clock signal in synchronization with the data signal in the communication;
• and
• a third signal contact configured to start the communication with the accessory via the first signal contact in response to a change of a potential of the third signal contact in a state where the electronic apparatus is attached to the accessory,
• wherein the first signal contact and the second signal contact are arranged next to each other, and
• wherein the third signal contact is disposed on an opposite side than the second signal contact with respect to the first signal contact.