Patent ID: 8019322

Claim:
An electronic equipment configured to limit use thereof and to release limit of the use thereof based on sending and receiving of an authentication signal to and from a key that is apart from the electronic equipment, comprising: a sending and receiving part configured to send and receive the authentication signal to and from the key; a signal level detection part configured to detect a signal level of a radio wave including the authentication signal, which is received from the key by the sending and receiving part; an authentication control part configured to determine whether or not the signal level detected by the signal level detection part is equal to or greater than a threshold value, an operation detection part configured to detect whether or not the electronic equipment is in operation; and an equipment use limiting signal generation part configured to generate an equipment use limiting signal for either limiting use of the electronic equipment, or releasing its limit, according to a result of determination by the authentication control part, wherein the authentication control part is further configured to change the threshold value according to whether or not the electronic equipment is in operation, which is detected by the operation detection part.