US3671679A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Arrangement for the recognition of loop closure in subscriber stations having semiconductor amplifiers fed via the connecting trunk
Assignee: International Standard Electric Corp
•
Filing: 1969-11-18
•
Granted: 1972-06-20
•
Expires: 1989-11-18
Abstract
Abstract An arrangement is provided for the recognition of call initiating loop closure in telephone subscriber stations employing semi-conductor amplifiers fed over a connecting trunk. On loop-closure, there is first created a virtual short circuit in the supervisory current direction. After recognition, the exchange switches over to the feed current direction for the amplifiers in the subscriber station. In this way the loop closure criterion is made independent of the d-c resistance of the amplifiers.
Inventors
- 👤 Hans Ulrich Knauer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:06
CPC Classifications
H; H04; H04M; H04M19/00; H04M19/08
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
156 words
A circuit arrangement for the recognition of call-initiating loop closure in telecommunication systems having subscriber stations which include a semi-conductor speech amplifier fed via a connecting trunk to a central exchange, the circuit arrangement comprising a diode element shunting the subscriber line at the input of the subscriber station so as to virtually short circuit the supervisory circuit means in the central exchange in a first direction of current flow in response to call-initiating loop closure of the subscriber loop, and supervisory circuit means, at the system exchange, responsive to the flow of current in said first direction, for causing the current to flow in the opposite direction in the loop and to energize thereby the semi-conductor amplifier at the subscriber station, said supervisory circuit means including a feed circuit and a pair of contacts, one of which is in each of the speech lines of the trunk coupling the feed circuit to the subscriber station.
Claim 2
Dependent Claim
156 words
A circuit arrangement for the recognition of call-initiating loop closure in telecommunication systems having subscriber stations which include a semi-conductor speech amplifier fed via a connecting trunk to a central exchange, the circuit arrangement comprising a diode element shunting the subscriber line at the input of the subscriber station so as to virtually short circuit the supervisory circuit means in the central exchange in a first direction of current flow in response to call-initiating loop closure of the subscriber loop, and supervisory circuit means, at the system exchange, responsive to the flow of current in said first direction, for causing the current to flow in the opposite direction in the loop and to energize thereby the semi-conductor amplifier at the subscriber station, said supervisory circuit means including a feed circuit and a pair of contacts, one of which is in each of the speech lines of the trunk coupling the feed circuit to the subscriber station.
Claim 3
Dependent Claim
29 words
A circuit arrangement as claimed in claim 1, in which the feed circuit in the exchange includes means for providing a high resistance value in said supervisory current direction.
Claim 4
Dependent Claim
32 words
A circuit arrangement as claimed in claim 2, in which the feed circuit in the exchange further includes means for providing a low resistance value in said opposite direction of current flow.
Claim 5
Dependent Claim
157 words
A circuit arrangement for the recognition of call-initiating loop closure in telecommunication systems having subscriber stations which include, a semi-conductor speech amplifier fed via a connecting trunk to the central exchange, the circuit arrangement comprising a diode element shunting the subscriber station speech amplifier at the input terminals thereof so as to virtually short circuit the supervisory circuit means in the central exchange in a first direction of current flow in response to the call-initiating loop closure of the subscriber loop, and supervisory circuit means, at the system exchange, responsive to the flow of current in said first direction, for causing the current to flow in the opposite direction in the loop and to energize thereby the semiconductor amplifier at the subscriber station, said supervisory circuit means including a feed circuit and a pair of contacts, one of which is in each of the speech lines of the trunk coupling the feed circuit to the subscriber station.
Claim 6
Dependent Claim
157 words
A circuit arrangement for the recognition of call-initiating loop closure in telecommunication systems having subscriber stations which include, a semi-conductor speech amplifier fed via a connecting trunk to the central exchange, the circuit arrangement comprising a diode element shunting the subscriber station speech amplifier at the input terminals thereof so as to virtually short circuit the supervisory circuit means in the central exchange in a first direction of current flow in response to the call-initiating loop closure of the subscriber loop, and supervisory circuit means, at the system exchange, responsive to the flow of current in said first direction, for causing the current to flow in the opposite direction in the loop and to energize thereby the semiconductor amplifier at the subscriber station, said supervisory circuit means including a feed circuit and a pair of contacts, one of which is in each of the speech lines of the trunk coupling the feed circuit to the subscriber station.
Claim 7
Dependent Claim
29 words
A circuit arrangement as claimed in claim 4, in which the feed circuit in the exchange includes means for providing a high resistance value in said supervisory current direction.
Claim 8
Dependent Claim
34 words
A circuit arrangement as claimed in claim 5, in which the feed circuit in the exchange further includes means for providing a low resistance value in said opposite (feed current) direction of current flow.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |