Electronic key system

An electronic key system comprising:

• a vehicle-mounted device mounted to a vehicle;
• and
• a plurality of electronic keys, each wirelessly communicable with the vehicle-mounted device,
• wherein the electronic key system is configured to have:
• a normal mode in which a given processing is permitted to be executed by the vehicle-mounted device when a given wireless communication processing between the vehicle-mounted device and any one of the plurality of electronic keys is successfully completed;
• and
• a deactivated mode in which the given processing is inhibited from being executed by the vehicle-mounted device,
• wherein the vehicle-mounted device is configured to execute, in the normal mode, the given processing in response to receiving a reply signal from the one electronic key after transmitting a given radio signal to the one electronic key, during the given wireless communication processing, but not to execute, in the deactivated mode, the given processing even when receiving the reply signal after the transmitting of the radio signal;
• and
• wherein the one electronic key is configured to, in the normal mode, transmit the reply signal in response to receiving the radio signal, during the given wireless communication processing, but to, in the deactivated mode, avoid transmitting of the reply signal even when receiving the radio signal.