Remote-control access control device and method for operating the same
First Claim
1. A remote-control access control device, comprising:
- tripping means;
an unlocking unit;
a stationary transmitter and receiver unit responding to actuation of said tripping means for transmitting a question code signal with a field intensity, receiving an answer code signal, and furnishing an unlocking signal to said unlocking unit if the answer code signal matches a command code signal;
a portable transponder having a receiver receiving the question code signal, a transmitter transmitting the answer code signal, and a battery voltage; and
said stationary transmitter and receiver unit repeatedly transmitting the question code signal if no answer code signal has been received in response to an initial transmission, and means for modifying a signal parameter upon transmission of the answer code signal as a function of one of the field intensity of the question code signal and the battery voltage of the transponder.
2 Assignments
0 Petitions
Accused Products
Abstract
A remote-control access control device, particularly for motor vehicles, includes a stationary transmitter and receiver unit responding to actuation of tripping means for transmitting a question code signal, receiving an answer code signal, and furnishing an unlocking signal to an unlocking unit if the answer code signal matches a command code signal. A portable transponder has a receiver receiving the question code signal and a transmitter transmitting the answer code signal. The question code signal is repeatedly transmitted if no answer code signal has been received in response to an initial transmission, and a signal parameter is modified upon transmission of the answer code signal as a function of a field intensity of the question code signal or of a battery voltage of the transponder. Alternatively, a signal parameter is modified when the answer code signal is transmitted if an information content of the question code signal indicates an emergency operation state. As another alternative, the transmitter and receiver unit has both a transmission channel for receiving signals of low field intensity and a transmission channel for receiving signals of high field intensity. A method is also provided for operating the access control device.
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Citations
26 Claims
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1. A remote-control access control device, comprising:
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tripping means; an unlocking unit; a stationary transmitter and receiver unit responding to actuation of said tripping means for transmitting a question code signal with a field intensity, receiving an answer code signal, and furnishing an unlocking signal to said unlocking unit if the answer code signal matches a command code signal; a portable transponder having a receiver receiving the question code signal, a transmitter transmitting the answer code signal, and a battery voltage; and said stationary transmitter and receiver unit repeatedly transmitting the question code signal if no answer code signal has been received in response to an initial transmission, and means for modifying a signal parameter upon transmission of the answer code signal as a function of one of the field intensity of the question code signal and the battery voltage of the transponder. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A remote-control access control device, comprising:
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tripping means; an unlocking unit; a stationary transmitter and receiver unit responding to actuation of said tripping means for transmitting a question code signal, receiving an answer code signal, and furnishing an unlocking signal to said unlocking unit if the answer code signal matches a command code signal; a portable transponder having a receiver receiving the question code signal and a transmitter transmitting the answer code signal; and means for modifying a signal parameter when the answer code signal is transmitted if an information content of the question code signal indicates an emergency operation state. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. remote-control access control device, comprising:
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tripping means; an unlocking unit; a stationary transmitter and receiver unit responding to actuation of said tripping means for transmitting a question code signal, receiving an answer code signal, and furnishing an unlocking signal to said unlocking unit if the answer code signal matches a command code signal; and a portable transponder having a transmitter transmitting the answer code signal and a receiver receiving the question code signal; said transmitter and receiver unit having both a transmission channel for receiving signals of low field intensity and a transmission channel for receiving signals of high field intensity. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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25. A method for operating a remote-access control device, which comprises:
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transmitting a question code signal from a stationary transmitter and receiver unit upon actuation of tripping means; receiving the question code signal at a transponder and transmitting an answer code signal from the transponder to the transmitter and receiver unit; comparing the answer code signal with a command code signal in the transmitter and receiver unit, and sending an unlocking signal to an unlocking unit if the answer code signal and the command code signal match; bringing the transponder to the vicinity of the transmitter and receiver unit and modifying a signal parameter if no unlocking signal has been tripped after the initial actuation of the tripping means; and
actuating the tripping means once again for transmitting the question code signal. - View Dependent Claims (26)
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Specification