Patent US3849772A successfully refreshed from Google Patents.
US3849772A
Expired / Lapsed
US
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Circuit integrity checking means for audio signal circuit
Assignee: SPX Technologies Inc
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Filing: 1973-08-06
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Granted: 1974-11-19
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Expires: 1993-08-06
Abstract
Abstract A means for checking the integrity of a cable pair dedicated to a public address system and having a plurality of loudspeakers bridged thereacross is disclosed. The integrity checking circuit comprises a line supervisory sensor which will provide an indication if there is an open in the dedicated cable pair and/or if there is a shunt below a predetermined minimum value. The loop is monitored through a D.C. circuit and an end of line impedance is provided for circuit continuity. A device, such as a capacitor, is used in series with each loudspeaker bridged across the line for blocking D.C. current. The line supervisory sensor has three states; one of which indicates that there is continuity in the dedicated line and that there is no shunt across the line which is below an acceptable minimum; another of which indicates that the dedicated line has an open; and the last of which indicates that there is a shunt across the line which has a value below an acceptable minimum. The line supervisory sensor may comprise a two-step relay, a plurality of relays, an electronic circuit, or other techniques which may be convenient and expedient.
Inventors
- 👤 R Burnett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 23:35
CPC Classifications
H; H04; H04R; H04R29/00; H04R29/007; G; G01; G01R; G01R31/00; G01R31/50; G01R31/52; G01R31/54; G01R31/58; H04R27/00
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
172 words
A direct current supervisory circuit for verifying the circuit integrity of a cable pair across which a plurality of audio devices may be bridged and comprising: a. a direct current blocking device in series with each of said audio devices for restricting the passage of direct current through said audio devices; b. an impedance bridged across said cable pair, near the remote end thereof, for providing a direct current circuit across said cable pair; and c. a three state line supervisory sensor in series with a direct current power supply and selectively bridged across the near end of said cable pair for; 1. indicating the circuit continuity of said cable pair when said line supervisory sensor is in a first of its three states; 2. indicating the lack of circuit continuity of said cable pair when said line supervisory sensor is in a second of its three states; and 3. indicating a low impedance, shunt across said cable pair when said line supervisory sensor is in a third of its three states.
Claim 2
Dependent Claim
172 words
A direct current supervisory circuit for verifying the circuit integrity of a cable pair across which a plurality of audio devices may be bridged and comprising: a. a direct current blocking device in series with each of said audio devices for restricting the passage of direct current through said audio devices; b. an impedance bridged across said cable pair, near the remote end thereof, for providing a direct current circuit across said cable pair; and c. a three state line supervisory sensor in series with a direct current power supply and selectively bridged across the near end of said cable pair for; 1. indicating the circuit continuity of said cable pair when said line supervisory sensor is in a first of its three states; 2. indicating the lack of circuit continuity of said cable pair when said line supervisory sensor is in a second of its three states; and 3. indicating a low impedance, shunt across said cable pair when said line supervisory sensor is in a third of its three states.
Claim 3
Dependent Claim
24 words
indicating the lack of circuit continuity of said cable pair when said line supervisory sensor is in a second of its three states; and
Claim 4
Dependent Claim
24 words
indicating the lack of circuit continuity of said cable pair when said line supervisory sensor is in a second of its three states; and
Claim 5
Dependent Claim
125 words
An integrity check system for a two conductor line having at least one audio device bridged across it and comprising in combination: a. a direct current power supply for providing electrical energy, b. a line supervisory sensor selectively connected in series with said line and said direct current power supply for checking the integrity of said two conductor line; c. a terminating impedance bridged across said two conductor line for completing a direct current series circuit through said line supervisory sensor, said line, said direct current power supply and said terminating impedance; d. a direct current blocking element connected in series with said audio device for restricting the passage of direct current through said audio device, and wHerein e. said line supervisory sensor responds to:
Claim 6
Dependent Claim
125 words
An integrity check system for a two conductor line having at least one audio device bridged across it and comprising in combination: a. a direct current power supply for providing electrical energy, b. a line supervisory sensor selectively connected in series with said line and said direct current power supply for checking the integrity of said two conductor line; c. a terminating impedance bridged across said two conductor line for completing a direct current series circuit through said line supervisory sensor, said line, said direct current power supply and said terminating impedance; d. a direct current blocking element connected in series with said audio device for restricting the passage of direct current through said audio device, and wHerein e. said line supervisory sensor responds to:
Claim 7
Dependent Claim
15 words
a first low integrity line condition comprising an open, by assuming a second condition; and
Claim 8
Dependent Claim
15 words
a first low integrity line condition comprising an open, by assuming a second condition; and
Claim 9
Dependent Claim
6 words
below a first prescribed value; or
Claim 10
Dependent Claim
6 words
below a first prescribed value; or
Claim 11
Dependent Claim
38 words
above a second prescribed value; and d. alarm means coupled to said line supervisory sensor for providing a unique signal when said line supervisory sensor senses a current below or above said first and second prescribed values, respectively.
Claim 12
Dependent Claim
38 words
above a second prescribed value; and d. alarm means coupled to said line supervisory sensor for providing a unique signal when said line supervisory sensor senses a current below or above said first and second prescribed values, respectively.
Claim 13
Dependent Claim
47 words
a second low integrity line condition comprising a shunt below a predetermined value, by assuming a third condition; and f. alarm means coupled to said line supervisory sensor for providing a unique signal when said line supervisory sensor has assumed either of said second or third conditions.
Claim 14
Dependent Claim
47 words
a second low integrity line condition comprising a shunt below a predetermined value, by assuming a third condition; and f. alarm means coupled to said line supervisory sensor for providing a unique signal when said line supervisory sensor has assumed either of said second or third conditions.
Claim 15
Dependent Claim
38 words
The combination as set forth in claim 2 and including control means for decoupling said direct current power supply and said line supervisory sensor from said line and for coupling a source of audio signals to said line.
Claim 16
Dependent Claim
22 words
indicating a low impedance, shunt across said cable pair when said line supervisory sensor is in a third of its three states.
Claim 17
Dependent Claim
22 words
indicating a low impedance, shunt across said cable pair when said line supervisory sensor is in a third of its three states.
Claim 18
Dependent Claim
37 words
The combination as set forth in claim 3 and wherein said control means includes means for preventing said alarm means from providing said unique signal when said control means decouples said line supervisory sensor from said line.
Claim 19
Dependent Claim
17 words
The combination as set forth in claim 2 wherein said direct current blocking element comprises a capacitor.
Claim 20
Dependent Claim
62 words
The combination as set forth in claim 2 wherein said line supervisory sensor includes a two step relay which has a current of a first magnitude flowing through it when said line supervisory sensor has assumed said first condition and which has a lesser and larger current flowing therethrough when said line supervisory sensor has assumed said second and third conditions, respectively.
Claim 21
Dependent Claim
38 words
The combination as set forth in claim 2 wherein said line supervisory sensor includes first and second relays of which one is operated, neither is operated, or both are operated for said first, second and third conditions, respectively.
Claim 22
Dependent Claim
16 words
The combination as set forth in claim 7 wherein said relays are in a series connection.
Claim 23
Dependent Claim
15 words
The combination as set forth in claim 7 wherein said relays are connected in parallel.
Claim 24
Dependent Claim
45 words
The combination as set forth in claim 2 wherein said line supervisory sensor includes first and second transistors of which said first transistor is rendered conducting, said second transistor is rendered conducting, or both are rendered conducting for said first, second and third conditions, respectively.
Claim 25
Dependent Claim
134 words
An integrity check circuit for supervising the integrity of a line pair having at least one audio device bridged thereacross and comprising in combination: a. a capacitor in series with each audio device bridged across said line pair for blocking the passage of direct current through said audio devices; b. an impedance bridged across said line pair near one end thereof for providing a direct current path from one to the other of the lines of said line pair; c. a line supervisory sensor and a direct current power source coupled in series and bridged across said line pair near the other end thereof for sensing if the magnitude of the direct current in said line pair, which results from the connection of said direct current power source and said line supervisory sensor is;
Claim 26
Dependent Claim
134 words
An integrity check circuit for supervising the integrity of a line pair having at least one audio device bridged thereacross and comprising in combination: a. a capacitor in series with each audio device bridged across said line pair for blocking the passage of direct current through said audio devices; b. an impedance bridged across said line pair near one end thereof for providing a direct current path from one to the other of the lines of said line pair; c. a line supervisory sensor and a direct current power source coupled in series and bridged across said line pair near the other end thereof for sensing if the magnitude of the direct current in said line pair, which results from the connection of said direct current power source and said line supervisory sensor is;
Claim 27
Dependent Claim
16 words
The combination as set forth in claim 11 wherein said line supervisory sensor comprises electromechanical means.
Claim 28
Dependent Claim
17 words
The combination as set forth in claim 12 wherein said electromechanical means comprises a two step relay.
Claim 29
Dependent Claim
54 words
The combination as set forth in claim 12 wherein said electromechanical means comprises first and second relays of which one is operated, neither is operated and both are operated when the direct current in said line pair is within said prescribed values; below said first prescribed value and above said second prescribed value, resPectively.
Claim 30
Dependent Claim
40 words
The combination as set forth in claim 11 and including control means for selectively decoupling said direct current power source and said line supervisory sensor from said line pair and coupling a source of audio signals to said line pair.
Claim 31
Dependent Claim
38 words
The combination as set forth in claim 15 wherein said control means includes means for inhibiting said alarm means when said control means decouples said direct current power source and said line supervisory sensor from said line pair.
Claim 32
Dependent Claim
16 words
The combination as set forth in claim 11 wherein said line supervisory sensor comprises transistor means.
Claim 33
Dependent Claim
84 words
The combination as set forth in claim 17 wherein said line supervisory sensor comprises first and second transistors and wherein said: a. first transistor is rendered conducting when the direct current in said line pair is within said prescribed values; b. second transistor is rendered conducting when the direct current in said line pair is below said first prescribed value; and c. said first and second transistors are rendered conducting when the direct current in said line pair is above said second prescribed value.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-18 | 1978-05-20 | 1978-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-18 | 1982-05-20 | 1982-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-18 | 1986-05-20 | 1986-11-19 | $7700.00 | Window Closed / Lapsed |