EP0205401A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Tone-responsive circuit for activating an instrumentality interfacing system
Assignee: Versus Technology Inc
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Filing: 1986-06-02
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Granted: —
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Expires: 2006-06-02
Abstract
Abstract In activating a unit for monitoring a remote instrumentality, a tone-responsive circuit operates in accordance with an established duty cycle wherein, for a major portion of each cycle, current is drawn from the telephone lines-servicing the system at a rate which is within the range permitted by prevailing telephone regulations, to charge a capacitor over time, and wherein, for a minor portion of each cycle, the charge stored by the capacitor is used to briefly operate a tone detection circuit which is capable of determining whether or not the remote instrumentality is being interrogated. If no such tones are detected, the circuit continues its periodic operation as previously described. If tones indicating a desired interrogation are detected, the tone-responsive circuit activates the monitoring unit which is used to poll the instrumentality.
Inventors
- 👤 Yechiel Rosenfeld
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 09:48
CPC Classifications
H; H04; H04M; H04M11/00; H04M11/002
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
160 words
For use in connection with a system for interrogating a remote instrumentality over a telephone line, responsive to an activation signal, an activation circuit comprising: input means communicating with said telephone line and adapted to receive operating currents and said activation signal from said telephone line; means for storing current received from said telephone line; means for limiting said received current to less than that required to operate said interrogating system, operatively connecting said input means and said storage means, storage detecting means associated with said storage means, for detecting the storage of a selected amount of current, and for providing a triggering signal upon said detection; signal detecting means, for detecting the presence of said activation signal on said telephone line, and for causing the activation of said interrogation system in response to said detection; and switching means operatively connecting said storage means and said signal detecting means, for operating said signal detecting means responsive to said triggering signal.
Claim 2
Dependent Claim
160 words
For use in connection with a system for interrogating a remote instrumentality over a telephone line, responsive to an activation signal, an activation circuit comprising: input means communicating with said telephone line and adapted to receive operating currents and said activation signal from said telephone line; means for storing current received from said telephone line; means for limiting said received current to less than that required to operate said interrogating system, operatively connecting said input means and said storage means, storage detecting means associated with said storage means, for detecting the storage of a selected amount of current, and for providing a triggering signal upon said detection; signal detecting means, for detecting the presence of said activation signal on said telephone line, and for causing the activation of said interrogation system in response to said detection; and switching means operatively connecting said storage means and said signal detecting means, for operating said signal detecting means responsive to said triggering signal.
Claim 3
Dependent Claim
20 words
The activation circuit of claim 1 wherein said triggering signal is periodic and continues until said activation signal is received.
Claim 4
Dependent Claim
20 words
The activation circuit of claim 1 wherein said storage element is either a capacitor or a voltage level detection circuit.
Claim 5
Dependent Claim
16 words
The activation circuit of claim 3 wherein said current limiting means is a regulated current source.
Claim 6
Dependent Claim
15 words
The activation circuit of claims 2 or 4 wherein said periodic signal is a sawtooth.
Claim 7
Dependent Claim
28 words
The activation circuit of claim 5 wherein said triggering signal is a series of pulses, having a width of not less than 60 nor more than 200 milliseconds.
Claim 8
Dependent Claim
17 words
The activation circuit of claim 1 wherein said current is limited to not more than 9.6 microamps.
Claim 9
Dependent Claim
26 words
The activation circuit of claim 1 wherein said activation signal is a pair of tones and wherein said signal detecting means is a tone detection circuit.
Claim 10
Dependent Claim
25 words
The activation circuit of claim 1 wherein said interrogation system further comprises means for monitoring said remote instrumentality upon the activation of said interrogation system.
Claim 11
Dependent Claim
19 words
The activation circuit of claim 9 wherein said monitoring means requires more than 9.6 microamps of current to operate.
Claim 12
Dependent Claim
54 words
The activation circuit of claim 1 wherein said telephone line assumes an on-hook condition when current drawn from said telephone line is maintained below a defined threshold, and said current limiting menas prevents the current drawn from said telephone line from exceeding said defined threshold and wherein said defined threshold is below 100 microamps.
Claim 13
Dependent Claim
13 words
The activation circuit of claim 11 wherein said defined threshold is 9.6 microamps.
Claim 14
Dependent Claim
94 words
The activation circuit of claim 11 wherein said telephone line is maintained in said on-hook condition until said signal detecting means detects the presence of said activation signal on said telephone line, and wherein said telephone line assumes an off-hook condition when current drawn from said telephone line exceeds said defined threshold, and wherein said telephone line is caused to assume said off-hook condition when said signal dectecting means detects the presence of said activation signal and further wherein said telephone line is returned to said on-hook condition after said interrogation has been completed.
References Cited (Backward Citations)
No citation records indexed.
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