US3781483A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Line feed and isolation transformer with integral loop supervision
Assignee: AT&T Inc
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Filing: 1971-12-02
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Granted: 1973-12-25
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Expires: 1991-12-02
Abstract
Abstract Apparatus is disclosed for providing all of the functions of battery-feed, isolation, and supervision for a line circuit in a communication switching system. The apparatus comprises a primary and a secondary winding coupled inductively via a magnetic core which includes an air gap. A reed contact pair is positioned across the air gap to operate and give indication of the presence of magnetic flux across the air gap resulting from current flow in the primary winding.
Inventors
- 👤 Deisch C Winston
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 00:32
CPC Classifications
H; H04; H04M; H04M3/00; H04M3/22; H04M3/2272
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
72 words
In a communication line circuit comprising a transformer having a first winding connected to a communication line, a second winding connected to a switching center and a magnetic core inductively coupling the first and second windings, said core including an air gap within said windings, the improvement which comprises a switch operable by the magnetomotive force across said air gap to give supervisory signal indications of the status of the communication line.
Claim 2
Dependent Claim
72 words
In a communication line circuit comprising a transformer having a first winding connected to a communication line, a second winding connected to a switching center and a magnetic core inductively coupling the first and second windings, said core including an air gap within said windings, the improvement which comprises a switch operable by the magnetomotive force across said air gap to give supervisory signal indications of the status of the communication line.
Claim 3
Dependent Claim
95 words
A communication line circuit having a first winding connected to an associated communication line; a communication system switching center termination having a second winding connected thereto; a magnetic core encircled by said windings for inductively coupling the communication line to the switching center termination through the first and second windings, the core including an air gap within said windings; and a reed switch positioned across the air gap and operable in response to magnetomotive force appearing across the air gap to give a signal indication of the appearance of supervisory signals on the communication line.
Claim 4
Dependent Claim
95 words
A communication line circuit having a first winding connected to an associated communication line; a communication system switching center termination having a second winding connected thereto; a magnetic core encircled by said windings for inductively coupling the communication line to the switching center termination through the first and second windings, the core including an air gap within said windings; and a reed switch positioned across the air gap and operable in response to magnetomotive force appearing across the air gap to give a signal indication of the appearance of supervisory signals on the communication line.
Claim 5
Dependent Claim
165 words
A communication line circuit comprising a first winding connectable to the associated line; a second winding connectable to a switching center; a magnetic core, having an air gap therein, for inductively coupling the first and second windings; a pair of contacts operable in response to the appearance of magnetomotive force across the air gap; and a hollow bobbin around which the first and second windings are wound; and wherein; the inductive coupling of the first and second windings is effective to permit signaling between a connected line and a connected switching center; and the operation of the pair of contacts is effective to give supervisory signal indications of the status of the connected line; the magnetic core is adapted to encircle the wound bobbin and includes a leg, having the air gap therein, positioned inside the hollow of the bobbin; and the pair of contacts are located across the air gap in the leg of the magnetic core and inside the hollow of the bobbin.
Claim 6
Dependent Claim
165 words
A communication line circuit comprising a first winding connectable to the associated line; a second winding connectable to a switching center; a magnetic core, having an air gap therein, for inductively coupling the first and second windings; a pair of contacts operable in response to the appearance of magnetomotive force across the air gap; and a hollow bobbin around which the first and second windings are wound; and wherein; the inductive coupling of the first and second windings is effective to permit signaling between a connected line and a connected switching center; and the operation of the pair of contacts is effective to give supervisory signal indications of the status of the connected line; the magnetic core is adapted to encircle the wound bobbin and includes a leg, having the air gap therein, positioned inside the hollow of the bobbin; and the pair of contacts are located across the air gap in the leg of the magnetic core and inside the hollow of the bobbin.
Claim 7
Dependent Claim
149 words
A communication system comprising a switching center including a switching network; a plurality of communication lines; a plurality of communication line circuits for connecting the communication lines to the switching center; means for interconnecting one of the communication lines with another selected one of the communication lines through the switching network; and isolation and supervision means associated with each of the lines and including a transformer comprising a first winding connected to the associated line, a second winding connected to the switching center, and a magnetic core encircled by said windings and having an air gap within said windings for inductively coupling the firsT and second windings to permit the transmission of signals between the line and the switching center; and a pair of reed contacts positioned across the air gap and responsive to the appearance of magnetomotive force across the air gap for producing supervisory signals indicative thereof.
Claim 8
Dependent Claim
149 words
A communication system comprising a switching center including a switching network; a plurality of communication lines; a plurality of communication line circuits for connecting the communication lines to the switching center; means for interconnecting one of the communication lines with another selected one of the communication lines through the switching network; and isolation and supervision means associated with each of the lines and including a transformer comprising a first winding connected to the associated line, a second winding connected to the switching center, and a magnetic core encircled by said windings and having an air gap within said windings for inductively coupling the firsT and second windings to permit the transmission of signals between the line and the switching center; and a pair of reed contacts positioned across the air gap and responsive to the appearance of magnetomotive force across the air gap for producing supervisory signals indicative thereof.
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) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |