US3815093A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Signaling system utilizing frequency burst duration and absence for control functions
Assignee: AFA SYST Inc
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Filing: 1973-05-11
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Granted: 1974-06-04
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Expires: 1993-05-11
Abstract
Abstract A signaling system has a plurality of remote transponders, which transmit signals, representative of the states of sensors associated with the transponders, to a central station in response to addressed interrogation signals transmitted by the central station. The interrogation signals include audio frequency bursts, whose width, in combination with the width of the space after the burst, indicates the address of the transponder group being interrogated. The state signals from the transponders also include frequency bursts, whose frequency indicates which transponder of a group having a particular address is responding and whose width indicates the state of the sensors associated with that transponder. The state signals cause display devices at the central station to indicate changes in the conditions at the remote monitors.
Inventors
- 👤 G Johnson
- 👤 H Caretto
- 👤 C Cook
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:15
CPC Classifications
G; G08; G08B; G08B26/00; G08B26/001; G08B26/003
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
234 words
A signaling system comprising: signal transmission means for transmitting state information; central station means for generating and applying an interrogation signal to said signal transmission means, for detecting a response signal from said signal transmission means and for displaying the state information represented by the characteristics of the response signal; the interrogation signal having predetermined characteristics and comprising at least a first burst of a first frequency, a first blank space, a second burst of the first frequency, and a second blank space; and at least one remote station means, connected in parallel with said central station means through said signal transmission means, for detecting the interrogation signal from said signal transmission means and for generating and applying at least one component of the response signal to said signal transmission means, said remote station means comprising at least one sensor means for indicating the state of conditions at said remote station means and at least one transponding means connected to said signal transmission means for generating at least one component of the response signal when at least the first burst and first space of the interrogation signal have particular predetermined characteristics; the component of the response signal generated being a burst of a second frequency having a predetermined characteristic dependent on the indication from said monitoring means and being applied to said signal transmission meaNs during the second blank space of the interrogation signal.
Claim 2
Dependent Claim
234 words
A signaling system comprising: signal transmission means for transmitting state information; central station means for generating and applying an interrogation signal to said signal transmission means, for detecting a response signal from said signal transmission means and for displaying the state information represented by the characteristics of the response signal; the interrogation signal having predetermined characteristics and comprising at least a first burst of a first frequency, a first blank space, a second burst of the first frequency, and a second blank space; and at least one remote station means, connected in parallel with said central station means through said signal transmission means, for detecting the interrogation signal from said signal transmission means and for generating and applying at least one component of the response signal to said signal transmission means, said remote station means comprising at least one sensor means for indicating the state of conditions at said remote station means and at least one transponding means connected to said signal transmission means for generating at least one component of the response signal when at least the first burst and first space of the interrogation signal have particular predetermined characteristics; the component of the response signal generated being a burst of a second frequency having a predetermined characteristic dependent on the indication from said monitoring means and being applied to said signal transmission meaNs during the second blank space of the interrogation signal.
Claim 3
Dependent Claim
40 words
A signaling system as claimed in claim 1 wherein said signal transmission means is a telephone facility in which at least parts of the telephone facility are voice grade channel, and the first and second frequencies are different audio frequencies.
Claim 4
Dependent Claim
26 words
A signaling system as claimed in claim 1 wherein said interrogation signal and said response signal are comprised of a series of bursts separated by spaces.
Claim 5
Dependent Claim
94 words
A signaling system as claimed in claim 1 including a plurality of remote station means each connected in parallel with said central station means through said signal transmission mean, said central station means being adapted to generate an interrogation signal having a plurality of different combinations of first bursts and first spaces of various predetermined durations, each different combination being associated with a separate one of said remote station means, each of said remote station means being adapted to detect its associated combination and to transpond the state of its monitor upon such detection.
Claim 6
Dependent Claim
103 words
A signaling system as claimed in claim 4 including a group of remote station means responsive to the same combination of first burst and first duration, each transponding means at each remote station means of said group having a plurality of monitors associated with it and generating a component of the response signal with a frequency different from the frequencies of the other transponding means of said group of remote station means and different from the first frequency of the interrogation signal, the width of the component of the response signal depending on the indications from the monitors associated with the transponding means.
Claim 7
Dependent Claim
143 words
A signaling system as claimed in claim 5 wherein said central station means comprises: decoding means for filtering the response signal to separate the components generated by each transponding means of said group of remote station means into frequency bursts of predetermined frequency, for comparing the durations of the frequency bursts with a reference, and for generating an alarm signal in response to the comparisons; display means for displaying the state of the monitors of the remote station; and control means for automatically generating the interrogation signal in response to internal signals so that the combinations of first bursts and first spaces occur in a prescribed manner and for activating the display means in response to the internal signals and the alarm signals from said decoding means whenever a change in the state of a monitoring means is indicated by the alarm signal.
Claim 8
Dependent Claim
53 words
A signaling system as claimed in claim 6 wherein said decoder means includes means for detecting the absence of a response burst signal and for generating a missing pulse signal in response to the detection, the missing pulse signal being used by said control means to indicate the failure of a remote station.
Claim 9
Dependent Claim
49 words
A signaling system as claimed in claim 6 wherein said control means includes means for generating data and time information signals which are used by said control means to cause said display means to indicate the date and time of a change in the state of a monitoring means.
Claim 10
Dependent Claim
36 words
A signaling system as claimed in claim 1, including an alarm inspector module connected to the transponding means for injecting an inspector signal into the response signal which indicates that the remote station is being tested.
References Cited (Backward Citations)
US3634824A
Cited
US3754215A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-03 | 1977-12-03 | 1978-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-03 | 1981-12-03 | 1982-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-03 | 1985-12-03 | 1986-06-04 | $7700.00 | Window Closed / Lapsed |