Patent US4720853A successfully refreshed from Google Patents.
US4720853A
Expired / Lapsed
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Ring signal discriminator
Assignee: CONCERTO INTERNATIONAL Inc
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Filing: 1987-03-09
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Granted: 1988-01-19
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Expires: 2007-03-09
Abstract
Abstract An improvement to automatic answering and call forwarding features used in telephone communications which allows a user to remotely activate, modify, and deactivate these features. The improvement describes a transformerless means for coupling signals to and from the telephone line without compromising the operation of the telephone line. The apparatus employs a microprocessor controller (11) with memory (12), a tone encoder (15), a tone decoder (14), a voice synthesizer (16), a timer (13), a cassette interface (17), an RS232C interface (20), a switching matrix (21), and a line interface (22). Audio, pulse dial, and tone signals are routed among the components and the telephone line (51) by the switching matrix (21) and line interface (22). The line interface (22) provides a transformerless means for coupling signals to and from the telephone line (51) and also analyzes the status of, and signals present on, the telephone line (51).
Inventors
- 👤 Aleksander Szlam
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:12
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/64; H04M1/65; H04M1/652; H04M1/654; H04M1/658; H04M3/00; H04M3/42; H04M3/54; Y; Y10; Y10S; Y10S379/00; Y10S379/903
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
189 words
A ring signal and dial pulse detector for detecting and discriminating among normal ringing signals, call forward reminder ringing signals, and rotary dial pulses on a telephone line and comprising: a capacitor for blocking D.C. voltages on said telephone line; optocoupler/isolator means connected across said telephone line and responsive to an input signal for providing a first output signal corresponding to, but electrically isolated from, said input signal; low pass filter means for eliminating high frequency signals and noise transitions in said first output signal; voltage comparator means for providing a second output signal responsive to the output voltage of said low pass filter means; retriggerable timer means responsive to said second output signal for providing a third output signal which is retriggerable and which continues for a predetermined period after the last transition of a predetermined polarity of said second output signal; and processor means responsive to the pulse width and repetition rate of said second and third output signals for providing a fourth output signal indicative of whether said input signal is a normal ringing signal, a call forward reminder ringing signal, or a rotary dial pulse.
Claim 2
Dependent Claim
189 words
A ring signal and dial pulse detector for detecting and discriminating among normal ringing signals, call forward reminder ringing signals, and rotary dial pulses on a telephone line and comprising: a capacitor for blocking D.C. voltages on said telephone line; optocoupler/isolator means connected across said telephone line and responsive to an input signal for providing a first output signal corresponding to, but electrically isolated from, said input signal; low pass filter means for eliminating high frequency signals and noise transitions in said first output signal; voltage comparator means for providing a second output signal responsive to the output voltage of said low pass filter means; retriggerable timer means responsive to said second output signal for providing a third output signal which is retriggerable and which continues for a predetermined period after the last transition of a predetermined polarity of said second output signal; and processor means responsive to the pulse width and repetition rate of said second and third output signals for providing a fourth output signal indicative of whether said input signal is a normal ringing signal, a call forward reminder ringing signal, or a rotary dial pulse.
Claim 3
Dependent Claim
15 words
The apparatus of claim 1 wherein said voltage comparator means has a predetermined hysteresis voltage.
Claim 4
Dependent Claim
28 words
The apparatus of claim 1 and further comprising: a rectifier means, connected between said capacitor and said optocoupler/isolator means, and operative to convert bipolar signals into unipolar signals.
Claim 5
Dependent Claim
15 words
The apparatus of claim 1 wherein said retriggerable timer means is a retriggerable monostable multivibrator.
Claim 6
Dependent Claim
25 words
The apparatus of claim 1 and further comprising: voltage reduction means between said optocoupler/isolator and said telephone line for altering the sensitivity of said optocoupler/isolator.
Claim 7
Independent Claim
171 words
A method for detecting and discriminating among normal ringing signals, call forward reminder ringing signals, and rotary dial pulses on a telephone line comprising: blocking D.C. voltages on said telephone line; providing a first output signal corresponding to, but electrically isolated from, an input signal on said telephone line; providing a filtered signal by low pass filtering said first output signal to eliminate high frequency signals and noise transitions in said first output signal; providing a second output signal responsive to the output voltage level of said filtered signal; providing a third output signal which is responsive to transitions of a predetermined polarity in said second output signals and which continues for a predetermined period after the last transition of said predetermined polarity of said second output signal; and analyzing the pulse width and repetition rate of said second and third output signals for providing a fourth output signal indicative of whether said input signal is a normal ringing signal, a call forward reminder ringing signal, or a rotary dial pulse.
Claim 8
Independent Claim
171 words
A method for detecting and discriminating among normal ringing signals, call forward reminder ringing signals, and rotary dial pulses on a telephone line comprising: blocking D.C. voltages on said telephone line; providing a first output signal corresponding to, but electrically isolated from, an input signal on said telephone line; providing a filtered signal by low pass filtering said first output signal to eliminate high frequency signals and noise transitions in said first output signal; providing a second output signal responsive to the output voltage level of said filtered signal; providing a third output signal which is responsive to transitions of a predetermined polarity in said second output signals and which continues for a predetermined period after the last transition of said predetermined polarity of said second output signal; and analyzing the pulse width and repetition rate of said second and third output signals for providing a fourth output signal indicative of whether said input signal is a normal ringing signal, a call forward reminder ringing signal, or a rotary dial pulse.
References Cited (Backward Citations)
US4049916A
Cited
US4475009A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-01-18 | 1991-07-20 | 1992-01-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-01-18 | 1995-07-20 | 1996-01-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-01-18 | 1999-07-20 | 2000-01-19 | $7700.00 | Window Closed / Lapsed |