Rolling code security system
1 Assignment
0 Petitions
Accused Products
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.
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Citations
41 Claims
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1-16. -16. (Cancelled).
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17. A method of sending codes to operate a controller for a barrier movement operator, the method comprising:
rf transmitting in trinary format a sequence of security codes, the sequence of security codes comprising a first code having a first relationship to a security code stored in the controller such that the first code will not cause operation of the controller and an additional code, which has a second relationship to the first code of the sequence for causing operation of the controller. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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25. A method of operating a transmitter to operator a controller for a barrier movement operator which includes an algorithm to generate a sequence of generated security codes in which a predetermined portion of a security code differs from the predetermined portion of previous security codes in the sequence and which controller interprets received codes in trinary format to be one of an invalid window, a valid window or an insecure code window, the method of operating the transmitter comprising:
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rf transmitting in a trinary format, a first transmitted code representing a first security code to be interpreted as being in the insecure code window; and
rf transmitting in a trinary format after the transmission of the first transmitted code a second transmitted code representing a second security code having a predetermined relationship to the first code. - View Dependent Claims (26, 27, 28)
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29. A method of controlling by a transmitter, a barrier movement operator having stored therein a fixed code a first binary code, said first binary code having a counter value above the value which permits operation of the operator, the method comprising:
transmitting a radio frequency signal modulated in a trinary code format representing an interleaved fixed code and a second binary code having a predetermined relationship to the first binary code which permits operation of the operator.
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30. A trinary code for a transmitter that controls an operator for a barrier movement operator, said trinary code comprising an interleaved fixed code and a binary code the combination of which identifies the transmitter, said binary code having a counter value greater than that of a binary code previously transmitted by the transmitter, both of said binary codes having counter values greater than a predetermined counter value below which the operator does not operate.
- 31. A transmitter for controlling a controller for a barrier movement operator, comprising an rf transmitter which rf transmits, in trinary format, a sequence of security codes, the sequence of security codes comprising a first code having a first relationship to security code previously stored in the controller such that the first code will not cause operation of the controller and an additional code, which has a second relationship to the first code transmitted by the rf transmitter for causing operation of the controller.
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39. A remote actuation system comprising:
an rf transmitter to control an operator which includes an rf receiver and an algorithm to generate a sequence of security codes in which a predetermined portion of a generated security code differs from the predetermined portion of previous security codes in the sequence and which operator interprets security codes received from the rf transmitter, in trinary format, to be in one of an invalid window, a valid window or an insecure code window, and the rf transmitter includes apparatus which rf transmits in trinary format, a first transmitted code representing a first security code to be interpreted by the operator as being in the insecure code window and rf transmits in a trinary format after the transmission of the first transmitted code a second transmitted code representing a second security code having a predetermined relationship to the first code. - View Dependent Claims (40, 41)
Specification