Rolling code security system

• US 7,412,056 B2
• Filed: 09/29/2003
• Issued: 08/12/2008
• Est. Priority Date: 05/17/1995
• Status: Expired due to Fees

• Current Assignee: The Chamberlain Group, Inc. (The Chamberlain Group LLC)
• Original Assignee: The Chamberlain Group, Inc. (The Chamberlain Group LLC)
• Inventors: Fitzgibbon, James J., Farris, Bradford L.
• Primary Examiner(s): Barron, Jr.; Gilberto
• Assistant Examiner(s): ALMEIDA, DEVIN E
• Application Number:
  US10/674,259
• Publication Number:
  US 20040066936A1
• Time in Patent Office: 1,779 Days
• Field of Search: 380/239, 380/270, 380/262
• US Class Current: 380/262
• CPC Class Codes: G07C 2009/00214 by one push button
• CPC Class Codes: G07C 2009/0023 with encription of the transmittted data signal
• CPC Class Codes: G07C 2009/00253 dynamically, e.g. variable code - rolling code
• CPC Class Codes: G07C 2009/00555 comprising means to detect or avoid relay attacks
• CPC Class Codes: G07C 2009/00587 by battery
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 2009/00928 for garage doors
• CPC Class Codes: G07C 9/00182 operated with unidirectional data transmission between data carrier and locks
• CPC Class Codes: H04L 2209/80 Wireless network architectures or network communication protocols for wireless network security H04W12/00
• CPC Class Codes: H04L 2209/84 Vehicles
• CPC Class Codes: H04L 9/3226 using a predetermined code, e.g. password, passphrase or PIN network architectures or network communication protocols for supporting authentication of entities using passwords in a packet data network H04L63/083

Abstract

A rolling code transmitter is useful in a security system for providing secure encrypted RF transmission comprising an interleaved trinary bit fixed code and rolling code. A receiver demodulates the encrypted RF transmission and recovers the fixed code and rolling code. Upon comparison of the fixed and rolling codes with stored codes and determining that the signal has emanated from an authorized transmitter, a signal is generated to actuate an electric motor to open or close a movable barrier.

Claims

1. A transmitter for sending an encrypted signal to control an actuator, comprising:

oscillator for generating a radio frequency oscillatory signal;

apparatus for enabling the sending of an encrypted signal;

a memory having a fixed code stored therein;

code generator responsive to the enabling apparatus for generating a variable code, said variable code being different for each enabling by the enabling device;

apparatus for providing a code that is based on the fixed code;

apparatus for combining a trinary code version of the variable code with a trinary code version of the code, wherein the apparatus combines the trinary code version of the variable code with the trinary code version of the code by interleaving trinary bits for the trinary code version of the variable code with trinary bits for the trinary code version of the code to thereby provide an interleaved trinary code combined result;

transmitting apparatus for modulating the radio frequency oscillatory signal with the interleaved trinary code combined result to produce a modulated trinary code variable radio frequency signal for operation or control of a secure actuator.

2. The transmitter of claim 1 wherein the apparatus for combining a trinary code version of the variable code with a trinary code version of the fixed code comprises an apparatus for combining a binary-coded trinary code version of the variable code with a binary-coded trinary code version of the fixed code.