Patent ID: 6043752
Filing Date: 2000-03-28
Classification: B60R,G07C

Abstract:
A remote-control unit for vehicles, incorporated in a key to be fitted into a key cylinder for starting an engine of a vehicle, for communicating with said vehicle, comprising:a reception circuit for receiving a cryptographic code transmitted from said vehicle when said key is fitted into said key cylinder;a memory circuit for storing said cryptographic code;a manual switch to be handled by a user;a control circuit for producing a first cipher system code responsively to reception of said cryptographic code, and producing a second cipher system code responsively to handling of said manual switch, wherein said control circuit produces said second cipher system code, which is different for each communication, on the basis of said cryptographic code stored in said memory circuit; anda transmission circuit for transmitting said first and second cipher system codes in the form of radio waves to said vehicle,wherein said first cipher system code contains a command for permitting engine start for said vehicle; andsaid second cipher system code is produced on the basis of a cryptographic code existent in said memory circuit and contains a command for closing or opening the door lock of said vehicle.