Importance

Loading Importance Indicators...

Abstract

A device for limiting access to authorized users, for example, a vehicle access limiting device, includes a control device and a key device. The control device has memory wherein a preset user code and a preset secret code are stored. The key device has a transponder which includes a memory for storing the user code and the secret code transferred from the control device. The transponder emits the user code which has been encoded with the transferred secret code. The control device includes a comparison device which allows access only when the encoded user code emitted by the transponder agrees with preset information stored in the control device. The key device also includes a comparison device which prevents overwriting of the taught secret code unless it also receives the taught user code. In the event of failure of the control device, a second control device with a new user code and a new secret code can be used with the key device, after which the second control device teaches the key device the new user code and the new secret code.

Loading the Abstract Image...

First Claim