US3816669A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for detecting telephone ringing signals
Assignee: Electrospace Corp
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Filing: 1972-11-01
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Granted: 1974-06-11
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Expires: 1992-11-01
Abstract
Abstract A ringing signal detector connectable to telephone lines and to an answering machine control circuit has a tuned transformer filter which has a center frequency and a bandwidth selected to pass 20 Hertz ringing signals on the telephone lines to the control circuit while substantially preventing the passage of lower frequency 10 Hertz revert dialing signals. The transformer has a floating primary having two input terminals each of which is connected to a series connected resistor-capacitor combination. A neon lamp extends between the two terminals from points intermediate the resistors and capacitors.
Inventors
- 👤 K Meri
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:41
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/64; H04M1/65; H04M1/654
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
165 words
In a telephone answering machine for use with incoming telephone lines which are connected to a telephone and carry ringing signals having predetermined frequency components as well as signals having frequency components other than those of the ringing signals including dialing signals generated by the telephone during dialing, and wherein the answering machine includes control circuit means; the combination comprising ringing detector means including input circuit means adapted to be coupled to the telephone lines for receiving the signals on the telephone lines; output circuit means connected to the control circuit means; and filter means having attenuating characteristics to pass ringing signals from said input to said output circuit means while substantially attenuating the dialing signals generated by the telephone and applied to the telephone lines, whereby the telephone answering machine is only activated by the ringing signals which pass through said filter means and not activated by the dialing signals which are substantially attenuated before reaching the telephone answering machine by said filter means.
Claim 2
Dependent Claim
165 words
In a telephone answering machine for use with incoming telephone lines which are connected to a telephone and carry ringing signals having predetermined frequency components as well as signals having frequency components other than those of the ringing signals including dialing signals generated by the telephone during dialing, and wherein the answering machine includes control circuit means; the combination comprising ringing detector means including input circuit means adapted to be coupled to the telephone lines for receiving the signals on the telephone lines; output circuit means connected to the control circuit means; and filter means having attenuating characteristics to pass ringing signals from said input to said output circuit means while substantially attenuating the dialing signals generated by the telephone and applied to the telephone lines, whereby the telephone answering machine is only activated by the ringing signals which pass through said filter means and not activated by the dialing signals which are substantially attenuated before reaching the telephone answering machine by said filter means.
Claim 3
Dependent Claim
14 words
The combination defined in claim 1, wherein said filter means comprises a band-pass filter.
Claim 4
Dependent Claim
17 words
The combination defined in claim 2, wherein said band-pass filter has a center frequency of 20 Hz.
Claim 5
Dependent Claim
16 words
The combination defined in claim 3, wherein said band-pass filter has 3-db bandwidth of 6 Hz.
Claim 6
Dependent Claim
15 words
The combination defined in claim 2, wherein said band-pass filter comprises a tuned transformer stage.
Claim 7
Dependent Claim
28 words
The combination defined in claim 5, wherein said tuned transformer stage has output terminals constituting said output circuit means; and input terminals connected to said input circuit means.
Claim 8
Dependent Claim
36 words
The combination defined in claim 6, wherein said tuned transformer stage comprises a transformer having physically isolated primary and secondary windings; and capacitance means conNected across the primary winding of said transformer for tuning the latter.
Claim 9
Dependent Claim
15 words
The combination defined in claim 7, wherein said primary winding is a floating primary winding.
Claim 10
Dependent Claim
28 words
The combination defined in claim 1, wherein said input circuit means comprises high impedance means for providing a high impedance between the telephone lines and said filter means.
Claim 11
Dependent Claim
37 words
The combination defined in claim 9, wherein said input circuit means has two leads connectable to a telephone line, and wherein said high impedance means comprises a series connected resistor in at least one of said leads.
Claim 12
Dependent Claim
15 words
The combination defined in claim 10, wherein a series resistor is connected in each lead.
Claim 13
Dependent Claim
22 words
The combination defined in claim 11, wherein said resistor has a resistance equal to a value in the range of 100 kilohms.
Claim 14
Dependent Claim
27 words
The combination defined in claim 1, wherein said input circuit means comprises DC isolating means for isolating direct currents on the telephone lines from said filter means.
Claim 15
Dependent Claim
36 words
The combination defined in claim 13, wherein said input circuit means has two leads connectable to a telephone line, and wherein said isolating means comprises a series connected capacitor in at least one of said leads.
Claim 16
Dependent Claim
15 words
The combination defined in claim 14, wherein a series capacitor is connected in each lead.
Claim 17
Dependent Claim
32 words
The combination defined in claim 1, wherein the other signals have widely ranging amplitudes, and wherein said input circuit means comprises attenuating means for attenuating the other signals having the larger amplitudes.
Claim 18
Dependent Claim
33 words
The combination defined in claim 16, wherein said input circuit means has two leads connectable to a telephone line, and wherein said attenuating means comprises a neon lamp connected across the two leads.
Claim 19
Dependent Claim
64 words
The combination defined in claim 1, wherein said input circuit means comprises two leads each connectable to a telephone line and to said filter means, and further comprising direct current decoupling means and high impedance means connected at a connecting point in series in at least one of said leads; and other signal attenuating means connected between said connecting point and the other lead.
Claim 20
Dependent Claim
44 words
The combination defined in claim 18, further comprising direct current decoupling means and high impedance means connected at another connecting point in series in the other lead, and wherein said other signal attenuating means is connected between said one and said other connecting points.
Claim 21
Dependent Claim
102 words
A telephone ringing signal detector connected to telephone lines which are connected to a telephone and which carry ringing signals having predetermined frequency components as well as signals having frequency components other than those of the ringing signals including dialing signals generated by the telephone during dialing; said ringing signal detector comprising input circuit means adapted to be coupled to the telephone lines for receiving the signals on the latter; output circuit means; and filter means having attenuating characteristics to pass the ringing signals from said input to said output circuit means while substantially attenuating the other signals on the telephone lines.
Claim 22
Dependent Claim
102 words
A telephone ringing signal detector connected to telephone lines which are connected to a telephone and which carry ringing signals having predetermined frequency components as well as signals having frequency components other than those of the ringing signals including dialing signals generated by the telephone during dialing; said ringing signal detector comprising input circuit means adapted to be coupled to the telephone lines for receiving the signals on the latter; output circuit means; and filter means having attenuating characteristics to pass the ringing signals from said input to said output circuit means while substantially attenuating the other signals on the telephone lines.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-10 | 1977-12-10 | 1978-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-10 | 1981-12-10 | 1982-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-10 | 1985-12-10 | 1986-06-11 | $7700.00 | Window Closed / Lapsed |