Advanced embedded code hopping system having master fixed code encryption

• US 5,914,667 A
• Filed: 09/15/1997
• Issued: 06/22/1999
• Est. Priority Date: 05/22/1992
• Status: Expired due to Term

• Current Assignee: Directed, LLC (VOXX International Corporation)
• Original Assignee: DEI Holdings Incorporated
• Inventors: Chen, Charles, Birchfield, Jerry W., Issa, Darrell E.
• Primary Examiner(s): Zimmerman, Brian
• Assistant Examiner(s): WILSON JR, WILLIAM HALL
• Application Number:
  US08/931,102
• Time in Patent Office: 645 Days
• Field of Search: 380/37, 380/9, 380/21, 380/23, 380/28, 380/25, 380/29, 375/200, 375/202, 375/203, 340/825.3, 340/825.31, 340/825.34, 340/825.56, 340/825.69, 340/825.72, 340/825.57, 340/825.62, 340/825.71, 370/203
• US Class Current: 340/5.26
• CPC Class Codes: B60R 2025/1013 Alarm systems characterised by the type of warning signal, e.g. visual, audible
• CPC Class Codes: B60R 25/1003 Alarm systems characterised by arm or disarm features
• CPC Class Codes: B60R 25/1004 Alarm systems characterised by the type of sensor, e.g. current sensing means using door lock sensors B60R25/1001
• CPC Class Codes: B60R 25/1018 Alarm systems characterised by features related to the general power supply
• CPC Class Codes: B60R 25/104 characterised by the type of theft warning signal, e.g. visual or audible signals with special characteristics
• CPC Class Codes: B60R 25/24 using electronic identifiers containing a code not memorised by the user
• CPC Class Codes: G01P 13/00 Indicating or recording presence, absence, or direction, of movement electric switches H01H; counting moving objects G06M7/00
• CPC Class Codes: G01P 15/0891 with indication of predetermined acceleration values G01P15/135 takes precedence
• CPC Class Codes: G07C 2009/00238 the transmittted data signal containing a code which is changed
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 2009/00849 programming by learning
• CPC Class Codes: G07C 9/00182 operated with unidirectional data transmission between data carrier and locks
• CPC Class Codes: G07C 9/21 having a variable access code
• CPC Class Codes: G07C 9/28 the pass enabling tracking or indicating presence
• CPC Class Codes: G08B 13/1436 with motion detection
• CPC Class Codes: G08B 25/007 Details of data content structure of message packets; data protocols
• CPC Class Codes: G08B 25/018 Sensor coding by detecting magnitude of an electrical parameter, e.g. resistance
• CPC Class Codes: G08B 25/10 using wireless transmission systems G08B25/009 takes precedence
• CPC Class Codes: G08B 29/24 Self-calibration, e.g. compensating for environmental drift or ageing of components
• CPC Class Codes: G08B 29/26 by updating and storing reference thresholds
• CPC Class Codes: G08C 17/02 : using a radio link
• CPC Class Codes: G08C 19/22 : by varying the duration of individual pulses
• CPC Class Codes: G08C 19/28 : using pulse code
• CPC Class Codes: G08C 2201/51 : Remote controlling of devices based on replies, status thereof
• CPC Class Codes: G08C 2201/62 : Rolling code
• CPC Class Codes: H04J 13/0074 : Code shifting or hopping

Abstract

A system for monitoring and controlling an area comprising a controller for controlling system operational functions; at least one remote-control transmitter for transmitting system commands to the controller in a code word having a fixed word and a hopping word therein; the fixed word comprising at least one fixed data bit and the hopping word comprising at least one changing data bit, wherein the hopping word changes its binary value from transmission to transmission of the system commands; and, means for scrambling bits of the fixed word and bits of the hopping word within the code word.

Claims

1. A system for monitoring and controlling an area comprising:

a) a controller for executing at least one system command;

b) at least one remote control transmitter for transmitting said system command to said controller in a scrambled code word having a fixed word and a hopping word;

c) said fixed word comprising at least one fixed data bit;

d) said hopping word comprising at least one changing data bit, wherein said hopping word changes each time said scrambled code word is transmitted from said transmitter;

e) a processor accessible to said transmitter scrambling at least one of said bits of said fixed word and at least one of said bits of said hopping word using a format word;

f) said controller using a master fixed code format word stored in at least one memory accessible to said controller to locate master fixed bits of said scrambled code word;

g) a master fixed algorithm stored in said memory accessible to said controller, deriving said format word by operating said master fixed algorithm in conjunction with said master fixed bits; and

h) said controller deriving said fixed word and said hopping word from said received scrambled code word using said format word.

2. The system of claim 1 wherein said fixed word includes at least one bit therein and said hopping word includes a number of bits therein.

3. The system of claim 1 wherein said hopping word includes at least one bit therein and said fixed word includes a number of bits therein.

4. The system of claim 1 further comprising a hopping algorithm modifying said hopping word of said transmitter n-times in response to n-times activation of said transmitter and modifying said hopping word m-times within said controller upon receipt of said code word m-times from said transmitter.

5. The system of claim 4 wherein said hopping algorithm is a pointer to a look-up table containing at least one binary word therein, said look-up table programmed in in at least one memory accessible to said transmitter and said memory accessible to said controller.

6. The controller of claim 4 further comprising:

a) calculating means for modifying said hopping word, received by said controller from said transmitter, with said hopping algorithm (m+x)-times to create a modified hopping word and comparing said modified hopping word with said n-time modified hopping word received from said transmitter if said n-time modified and said m-time modified hopping words do not match; and

,

b) said controller storing said transmitter hopping word in said memory accessible to said controller if said hopping words do not match after performing said hopping algorithm (m+x) times.

7. The controller of claim 4 further including:

a) a processor modifying said hopping word, received by said controller from said transmitter, with said hopping algorithm (m+x)-times to create a modified hopping word and comparing said modified hopping word with said n-time modified hopping word received from said if said n-time modified and said m-time modified hopping words do not match; and

b) said controller storing said transmitter hopping word in said memory accessible to said controller if said hopping words do not match after performing said hopping algorithm (m+x) times.

8. The system of claim 4 further comprising a learn mode for programming last received hopping word of said transmitter by said controller in said memory accessible to said controller as a 0-time modified hopping word of said controller, thereby providing an initial match between said hopping words of said transmitter and said controller.

9. The system of claim 1 wherein said hopping algorithm changes at least one said fixed bit.

10. The system of claim 1 further comprising:

a) an identification code particular to said transmitter and,

b) said controller storing said identification code for identification of said transmitter.

11. The transmitter of claim 10 further comprising at least one memory accessible to said transmitter for storing at least one said identification code therein.

12. The controller of claim 10 further comprising at least one memory accessible to said controller for storing at least one said identification code therein.

13. The system of claim 10 wherein said controller executes said system command transmitted from said transmitter having said authorized identification code.

14. The system of claim 13 wherein said system command transmitted by said transmitter is executed by said controller when said n-times modified hopping word transmitted by said transmitter and m-times modified hopping word of said controller are identical.

15. The system of claim 1 further comprising a transmission from said transmitter comprising a continuous series of said code words, said transmission initiated by activation of a switch integral to said transmitter and terminated by deactivation of said switch.

16. The system of claim 15 wherein said code words within said transmission are identical.

17. The system of claim 1 further comprising:

a) a first memory accessible to said transmitter, said first memory storing last modified hopping word transmitted to said controller;

b) a first processor, accessible to said transmitter, applying a hopping algorithm to said last modified hopping word to generate a new hopping word, said first processor storing said new hopping word in said first memory in response to activation of said transmitter;

c) a second memory accessible to said controller, said second memory storing last received hopping word from said transmitter;

d) a second processor accessible to said controller modifying said last received hopping word stored in said second memory to produce a modified hopping word, storing said modified hopping word in a third memory accessible to said second processor and comparing said modified hopping word with said new hopping word received from said transmitter;

e) storing said modified hopping word in said second memory if said modified hopping word matches said received hopping word from said transmitter; and

f) said second processor continuing to modify said modified hopping word stored in said third memory x-times if said modified word does not match said new hopping word received from said transmitter.

18. A system for monitoring and controlling an area comprising:

a) a controller for executing at least one system command;

b) at least one remote control transmitter for transmitting said at least one system command to said controller in at least one scrambled code word having at least one fixed word and at least one hopping word therein;

c) said fixed word including at least one fixed data bit;

d) said hopping word including at least one changing data bit, wherein said hopping word changes its value at least once each time said system command is transmitted;

e) at least one format word scrambling at least one of said bits of said fixed word and scrambling at least one of said bits of said hopping word within said code word to generate at least one scrambled code word transmitted from said transmitter to said controller;

f) said controller using a master fixed code format word stored in a memory accessible to said controller to locate master fixed bits of said code word;

g) at least one master fixed algorithm stored in said memory accessible to said controller, said controller deriving said format word by operating said master fixed algorithm in conjunction with said master fixed bits; and

h) said controller deriving said fixed word and said hopping word from said received code word using said format word.