US3660609A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Subscriber long line extender
Assignee: COMMUNICATIONS SYSTEMS CORP
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Filing: 1969-08-22
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Granted: 1972-05-02
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Expires: 1989-08-22
Abstract
Abstract A subscriber long line extender for use in the subscriber loop of a telephone network to extend the operating limits for the subscriber lines connecting a subscriber telephone to the central office equipment and the central office voltage source comprising a signalling circuit which is operably connected to brake the subscriber line and further operable in response to the current generated by the subscriber telephone being placed in an off-hook condition to provide closed circuit to the central office equipment indicative of the off-hook condition of the subscriber telephone and independent of any impedance in the subscriber loop. A second auxiliary feature of the subscriber long line extender provides for a hybrid amplifier to be used in conjunction with the above signalling circuit to enable simultaneous two-way transmissions between the subscriber telephone and the central office equipment, and an isolating means connected between the hybrid amplifier and the signalling circuit to prevent interaction between the signalling and amplification functions.
Inventors
- 👤 Hubert J Tremblay
- 👤 Frank V Mellien Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:17
CPC Classifications
H; H04; H04M; H04M19/00; H04M19/001; H04M19/006; H04B; H04B3/00; H04B3/02; H04B3/04; H04M3/00; H04M3/40
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
301 words
A telephone long line extender for a subscriber loop to extend the operating limits for subscriber lines connecting a subscriber telephone to the central office equipment and the central office voltage source, comprising: a first transistor, normally non-conductive; a second transistor, normally conductive; a third transistor, normally non-conductive; a first normally open switch means operably connected to said central office equipment through a first inductor; a relay winding connected in circuit with said third transistor wherein said relay winding is adapted to close said first switch means in response to a current flowing in said relay winding whereby said current flow from said subscriber telephone indicative of said off-hook condition causes said first transistor to conduct, causing said second transistor to be non-conductive thereby causing said third transistor to be conductive wherein a current is caused to flow through said relay winding thereby closing said switch means and providing a closed circuit through said inductor to said central office equipment indicative of said off-hook condition of said subscriber telephone and independent of any impedance in said subscriber loop; a two-way hybrid amplifier providing two-way transmission between said subscriber telephone and said central office equipment; second inductor means connected in said subscriber loop for isolating for isolating said first switch means, said first, second and third transistors and said relay winding from voice range audio frequency signals; a voltage booster circuit means connected to said second inductor means for increasing the voltage in said subscriber line, said voltage booster circuit not requiring an additional source of voltage, wherein said voltage booster circuit is operative only during said off-hook condition of said subscriber telephone; and ring diverter means intermittently operable adapted to provide a path for a ringing current between said central office equipment and said subscriber telephone thereby bypassing said first transistor.
Claim 2
Dependent Claim
301 words
A telephone long line extender for a subscriber loop to extend the operating limits for subscriber lines connecting a subscriber telephone to the central office equipment and the central office voltage source, comprising: a first transistor, normally non-conductive; a second transistor, normally conductive; a third transistor, normally non-conductive; a first normally open switch means operably connected to said central office equipment through a first inductor; a relay winding connected in circuit with said third transistor wherein said relay winding is adapted to close said first switch means in response to a current flowing in said relay winding whereby said current flow from said subscriber telephone indicative of said off-hook condition causes said first transistor to conduct, causing said second transistor to be non-conductive thereby causing said third transistor to be conductive wherein a current is caused to flow through said relay winding thereby closing said switch means and providing a closed circuit through said inductor to said central office equipment indicative of said off-hook condition of said subscriber telephone and independent of any impedance in said subscriber loop; a two-way hybrid amplifier providing two-way transmission between said subscriber telephone and said central office equipment; second inductor means connected in said subscriber loop for isolating for isolating said first switch means, said first, second and third transistors and said relay winding from voice range audio frequency signals; a voltage booster circuit means connected to said second inductor means for increasing the voltage in said subscriber line, said voltage booster circuit not requiring an additional source of voltage, wherein said voltage booster circuit is operative only during said off-hook condition of said subscriber telephone; and ring diverter means intermittently operable adapted to provide a path for a ringing current between said central office equipment and said subscriber telephone thereby bypassing said first transistor.
Claim 3
Dependent Claim
137 words
A telephone switching circuit having central office automatic billing equipment, a two-party subscriber line with a first and second subscriber telephone set wherein said second subscriber telephone has a ground connection introduced into said telephone when said telephone is in the off-hook position in combination with a long line extender including a subscriber loop, the improvement comprising: a differential relay connected in said subscriber loop; a normally open switch associated with said differential relay wherein said switch means closes when said differential relay is unbalanced; and means for connecting said differential relay to said two-partY subscriber line wherein said differential relay remains balanced when said first telephone is in said off-hook condition and unbalances when said second telephone is in said off-hook condition thereby closing said switch and automatically identifying said second telephone in said off-hook position.
Claim 4
Dependent Claim
137 words
A telephone switching circuit having central office automatic billing equipment, a two-party subscriber line with a first and second subscriber telephone set wherein said second subscriber telephone has a ground connection introduced into said telephone when said telephone is in the off-hook position in combination with a long line extender including a subscriber loop, the improvement comprising: a differential relay connected in said subscriber loop; a normally open switch associated with said differential relay wherein said switch means closes when said differential relay is unbalanced; and means for connecting said differential relay to said two-partY subscriber line wherein said differential relay remains balanced when said first telephone is in said off-hook condition and unbalances when said second telephone is in said off-hook condition thereby closing said switch and automatically identifying said second telephone in said off-hook position.
Claim 5
Dependent Claim
205 words
A telephone long line extender for a subscriber loop to extend the operating limits for a subscriber line connecting a subscriber telephone to the central office equipment and the central office voltage source, comprising: a signalling circuit operably connected to break the DC continuity of the subscriber line and further operable in response to the current flow through said subscriber telephone when said subscriber telephone is placed in an off-hook condition to provide a closed circuit to said central office equipment indicative of said off-hook condition of said subscriber telephone and independent of any impedance in said subscriber loop, said signalling circuit having a first normally open switch means operably connected to said central office equipment, and a transistor control circuit connected to said first switch means and to said subscriber line wherein said transistor control circuit senses said off-hook condition of said subscriber telephone thereby causing said first switch means to close and thereby actuating said central office equipment by providing said closed circuit; and voltage booster means for increasing the voltage in said subscriber line, said voltage booster means not requiring an additional source of voltage and wherein said voltage booster means is operative only during said off-hook condition of said subscriber telephone.
Claim 6
Dependent Claim
205 words
A telephone long line extender for a subscriber loop to extend the operating limits for a subscriber line connecting a subscriber telephone to the central office equipment and the central office voltage source, comprising: a signalling circuit operably connected to break the DC continuity of the subscriber line and further operable in response to the current flow through said subscriber telephone when said subscriber telephone is placed in an off-hook condition to provide a closed circuit to said central office equipment indicative of said off-hook condition of said subscriber telephone and independent of any impedance in said subscriber loop, said signalling circuit having a first normally open switch means operably connected to said central office equipment, and a transistor control circuit connected to said first switch means and to said subscriber line wherein said transistor control circuit senses said off-hook condition of said subscriber telephone thereby causing said first switch means to close and thereby actuating said central office equipment by providing said closed circuit; and voltage booster means for increasing the voltage in said subscriber line, said voltage booster means not requiring an additional source of voltage and wherein said voltage booster means is operative only during said off-hook condition of said subscriber telephone.
Claim 7
Dependent Claim
17 words
The long line extender of claim 3 wherein said first switch means comprises a glass reed switch.
Claim 8
Dependent Claim
107 words
The long line extender of claim 3 wherein said transistor control circuit comprises: a first transistor, normally non-conductive; a relay winding connected in circuit with said first transistor wherein said first switch means is actuable in response to a current flowing in said relay winding; and a first inductor means connected to said first switch means wherein said current flow from said subscriber telephone indicative of said off-hook condition causes said first transistor to conduct, wherein a current is caused to flow through said relay winding thereby closing said first switch means and providing said closed circuit to said central office equipment through said first inductor means.
Claim 9
Dependent Claim
57 words
The long line extender of claim 5 further comprising a differential relay in said subscriber loop; and second normally open switch means associated with said differential relay wherein said second switch means closes when said differential relay is unbalanced and wherein said closure is indicative of a ground connection on said subscriber telephone in said off-hook position.
Claim 10
Dependent Claim
18 words
The long line extender of claim 6 wherein said second switch means comprises a second glass reed switch.
Claim 11
Dependent Claim
254 words
A telephone long line extender for a subscriber loop to extend the operating limits for a subscriber line connecting a subscriber telephone to the central office equipment and the central office voltage source, comprising: a signalling circuit operably connected to break the DC continuity of the subscriber line and further operable in response to the current flow through said subscriber telephone when said subscriber telephone is placed in an off-hook condition to provide a closed circuit to said central office equipment indicative of said off-hook condition of said subscriber telephone and independent of any impedance in said subscriber loop, said signalling circuit including a first normally open switch means operably connected to said central office equipment, a first transistor normally non-conductive, a relay winding connected in circuit with said first transistor wherein said relay winding is adapted to close said first switch means in response to a current flowing in said relay winding, and a first inductor means connected to said first switch means wherein said current flow from said subscriber telephone indicative of said off-hook condition causes said first transistor to conduct, wherein a current is caused to flow through said relay winding thereby closing said first switch and providing said closed circuit to said central office equipment through said first inductor means; a two-way hybrid amplifier for enabling two-way transmission between said subscriber telephone and said central office equipment; and means operably connected between said signalling circuit and said hybrid amplifier for isolating said signalling circuit from voice range audio frequency signals.
Claim 12
Dependent Claim
254 words
A telephone long line extender for a subscriber loop to extend the operating limits for a subscriber line connecting a subscriber telephone to the central office equipment and the central office voltage source, comprising: a signalling circuit operably connected to break the DC continuity of the subscriber line and further operable in response to the current flow through said subscriber telephone when said subscriber telephone is placed in an off-hook condition to provide a closed circuit to said central office equipment indicative of said off-hook condition of said subscriber telephone and independent of any impedance in said subscriber loop, said signalling circuit including a first normally open switch means operably connected to said central office equipment, a first transistor normally non-conductive, a relay winding connected in circuit with said first transistor wherein said relay winding is adapted to close said first switch means in response to a current flowing in said relay winding, and a first inductor means connected to said first switch means wherein said current flow from said subscriber telephone indicative of said off-hook condition causes said first transistor to conduct, wherein a current is caused to flow through said relay winding thereby closing said first switch and providing said closed circuit to said central office equipment through said first inductor means; a two-way hybrid amplifier for enabling two-way transmission between said subscriber telephone and said central office equipment; and means operably connected between said signalling circuit and said hybrid amplifier for isolating said signalling circuit from voice range audio frequency signals.
Claim 13
Dependent Claim
22 words
The long line extender of claim 8 wherein said isolation means comprises a differential relay connected in circuit with said subscriber loop.
Claim 14
Dependent Claim
49 words
The long line extender of claim 9 further comprising: a second normally open switch means associated with said differential relay wherein said switch means closes when said differential relay is unbalanced and wherein said closure is indicative of a ground connection on said subscriber telephone in said off-hook position.
Claim 15
Dependent Claim
18 words
The long line extender of claim 10 wherein said second switch means comprises a second glass reed switch.
Claim 16
Dependent Claim
179 words
A telephone long line extender for a subscriber loop to extend the operating limits for a subscriber line connecting a subscriber telephone to the central office equipment and the central office voltage source, comprising: a signalling circuit operably connected to break the DC continuity of the subscriber line and further operable in response to the current flow through said subscriber telephone when said subscriber telephone is placed in an off-hook condition to provide a closed circuit to said central office equipment indicative of said off-hook condition of said subscriber telephone and independent of any impedance in said subscriber loop; a two-way hybrid amplifier for enabling two-way transmission between said subscriber telephone and said central office equipment; means operably connected between said signalling circuit and said hybrid amplifier for isolating said signalling circuit from voice range audio frequency signals; and a voltage booster means for increasing the voltage in said subscriber line, said voltage booster means not requiring an additional source of voltage and wherein said voltage booster means is operative only during said off-hook condition of said subscriber telephone.
Claim 17
Dependent Claim
179 words
A telephone long line extender for a subscriber loop to extend the operating limits for a subscriber line connecting a subscriber telephone to the central office equipment and the central office voltage source, comprising: a signalling circuit operably connected to break the DC continuity of the subscriber line and further operable in response to the current flow through said subscriber telephone when said subscriber telephone is placed in an off-hook condition to provide a closed circuit to said central office equipment indicative of said off-hook condition of said subscriber telephone and independent of any impedance in said subscriber loop; a two-way hybrid amplifier for enabling two-way transmission between said subscriber telephone and said central office equipment; means operably connected between said signalling circuit and said hybrid amplifier for isolating said signalling circuit from voice range audio frequency signals; and a voltage booster means for increasing the voltage in said subscriber line, said voltage booster means not requiring an additional source of voltage and wherein said voltage booster means is operative only during said off-hook condition of said subscriber telephone.
Claim 18
Dependent Claim
205 words
A telephone long line extender for a subscriber loop to extend the operating limits for a subscriber line connecting a subscriber telephone to the central office equipment and the central office voltage source, comprising: a signalling circuit operably connected to break the DC continuity of the subscriber line and further operable in response to the current flow through said subscriber telephone when said subscriber telephone is placed in an off-hook condition to provide a closed circuit to said central office equipment indicative of said off-hook condition of said subscriber telephone and independent of any impedance in said subscriber loop, said signalling circuit including a first normally open switch means operably connected to said central office equipment, and a transistor control circuit connected to said first switch means and to said subscriber line wherein said transistor control circuit senses said off-hook condition of said subscriber telephone thereby causing said first switch means to close and thereby actuating said central office equipment by providing said closed circuit; a two-way hybrid amplifier for enabling two-way transmission between said subscriber telephone and said central office equipment; and means operably connected between said signalling circuit and said hybrid amplifier for isolating said signalling circuit from voice range audio frequency signals.
Claim 19
Dependent Claim
205 words
A telephone long line extender for a subscriber loop to extend the operating limits for a subscriber line connecting a subscriber telephone to the central office equipment and the central office voltage source, comprising: a signalling circuit operably connected to break the DC continuity of the subscriber line and further operable in response to the current flow through said subscriber telephone when said subscriber telephone is placed in an off-hook condition to provide a closed circuit to said central office equipment indicative of said off-hook condition of said subscriber telephone and independent of any impedance in said subscriber loop, said signalling circuit including a first normally open switch means operably connected to said central office equipment, and a transistor control circuit connected to said first switch means and to said subscriber line wherein said transistor control circuit senses said off-hook condition of said subscriber telephone thereby causing said first switch means to close and thereby actuating said central office equipment by providing said closed circuit; a two-way hybrid amplifier for enabling two-way transmission between said subscriber telephone and said central office equipment; and means operably connected between said signalling circuit and said hybrid amplifier for isolating said signalling circuit from voice range audio frequency signals.
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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) | 1975-05-02 | 1975-11-01 | 1976-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-02 | 1979-11-01 | 1980-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-02 | 1983-11-01 | 1984-05-02 | $7700.00 | Window Closed / Lapsed |