US3925625A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transient controlled telephone line circuit
Assignee: AT&T Inc
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Filing: 1974-07-25
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Granted: 1975-12-09
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Expires: 1994-07-25
Abstract
Abstract There is disclosed a line circuit for use in the path between a switching machine and a telephone station for controlling communication services such as ringing and hold to the station. The line circuit is connected across the communication conduction pairs in a manner which allows removal without interrupting active telephone service. The transient signals which are generated whenever the station makes a transition from on-hook to off-hook and from off-hook to on-hook are used to obviate the need for line current detection. In this manner, the line relay is removed from the series path between the switching machine and the telephone station.
Inventors
- 👤 Ronald Joseph Angner
- 👤 Alexander Feiner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 00:50
CPC Classifications
H; H04; H04M; H04M9/00; H04M9/002; H04M9/005; H04M9/006
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
145 words
A line circuit for use in controlling communication services between a telephone switching machine and a telephone station, said line circuit adapted for connection in parallel across the communication conduction pair between said switching machine and said telephone station and adapted for A-lead control from said station, said line circuit means including hold means operable for maintaining a connection from said switching machine in an active noncommunicating condition, means for detecting signals on said A lead, means for providing transition control signals upon any transition of said telephone station from an off-hook condition to an on-hook condition, said transition control signals being provided in response to the transient signal generated when said telephone station becomes disconnected from said conduction pair, and means for enabling said hold means upon a detected signal from said A lead and the absence of said telephone station transition control signals.
Claim 2
Dependent Claim
145 words
A line circuit for use in controlling communication services between a telephone switching machine and a telephone station, said line circuit adapted for connection in parallel across the communication conduction pair between said switching machine and said telephone station and adapted for A-lead control from said station, said line circuit means including hold means operable for maintaining a connection from said switching machine in an active noncommunicating condition, means for detecting signals on said A lead, means for providing transition control signals upon any transition of said telephone station from an off-hook condition to an on-hook condition, said transition control signals being provided in response to the transient signal generated when said telephone station becomes disconnected from said conduction pair, and means for enabling said hold means upon a detected signal from said A lead and the absence of said telephone station transition control signals.
Claim 3
Dependent Claim
40 words
The invention set forth in claim 1 further comprising means for signaling the discoNnection of said station from said telephone switching machine upon a detected signal from said A lead and the provision of said telephone station transition control signals.
Claim 4
Dependent Claim
20 words
The invention set forth in claim 2 wherein said detected A lead signal is the absence of ground potential thereon.
Claim 5
Dependent Claim
32 words
The invention set forth in claim 1 wherein said means for providing transition control signals is further operable to detect ringing signals applied to said communication conduction pair from said switching machine.
Claim 6
Dependent Claim
29 words
The invention set forth in claim 1 wherein said hold means includes a relay the winding of which is connectable across said communication conduction pair from said switching machine.
Claim 7
Dependent Claim
48 words
The invention set forth in claim 1 wherein said means for providing transition control signals is operable to detect ringing signals applied to said communication conduction pair from said switching machine, and operable as a hold bridge for connection across said communication conduction pair from said switching machine.
Claim 8
Dependent Claim
121 words
A line circuit adapted for connection in parallel across the communication leads between a switching machine and a telephone station, said line circuit comprising a hold bridge connectable across said communication leads, and means for enabling said hold bridge under control of the joint interaction of transient signals and other signals generated from said station, said enabling means including transient response means operable under control of the transient signal generated when said telephone station makes an off-hook to on-hook transition or an on-hook to off-hook transition, said enabling means additionally including means operable under control of said other signals, said transient response means including a relay having two windings connected in series, said series windings capacitively coupled to said communication leads.
Claim 9
Dependent Claim
121 words
A line circuit adapted for connection in parallel across the communication leads between a switching machine and a telephone station, said line circuit comprising a hold bridge connectable across said communication leads, and means for enabling said hold bridge under control of the joint interaction of transient signals and other signals generated from said station, said enabling means including transient response means operable under control of the transient signal generated when said telephone station makes an off-hook to on-hook transition or an on-hook to off-hook transition, said enabling means additionally including means operable under control of said other signals, said transient response means including a relay having two windings connected in series, said series windings capacitively coupled to said communication leads.
Claim 10
Dependent Claim
28 words
The invention set forth in claim 7 wherein said hold bridge is a single winding of said relay, said single winding being directly connected across said communication leads.
Claim 11
Dependent Claim
143 words
A line circuit for use in controlling communication connections over communication leads between a telephone switching machine and a telephone station, said line circuit adapted for A-lead control between said line circuit comprising hold means for connection to said communication leads from said switching machine, said hold means operable for maintaining a connection from said switching machine in an active noncommunicating condition, means for monitoring said A lead, station network transition detection means momentarily operable upon station network connection to or disconnection from said communication leads, means for enabling said hold means upon a detected signal on said A lead and the non-operable condition of said station network transition detection means, and means for signaling the disconnection of said station from said switching machine upon a detected signal from said A lead and upon the momentary operation of said station network transition means.
Claim 12
Dependent Claim
143 words
A line circuit for use in controlling communication connections over communication leads between a telephone switching machine and a telephone station, said line circuit adapted for A-lead control between said line circuit comprising hold means for connection to said communication leads from said switching machine, said hold means operable for maintaining a connection from said switching machine in an active noncommunicating condition, means for monitoring said A lead, station network transition detection means momentarily operable upon station network connection to or disconnection from said communication leads, means for enabling said hold means upon a detected signal on said A lead and the non-operable condition of said station network transition detection means, and means for signaling the disconnection of said station from said switching machine upon a detected signal from said A lead and upon the momentary operation of said station network transition means.
Claim 13
Dependent Claim
30 words
The invention set forth in claim 9 wherein said station network transition detection means is connected in parallel across said communication leads between said switching machine and said telephone station.
Claim 14
Dependent Claim
30 words
The invention set forth in claim 10 wherein said station network transition detection means is further operable to detect ringing signals applied to said communication leads from said switching machine.
Claim 15
Dependent Claim
56 words
The invention set forth in claim 9 wherein said hold bridge includes a connection portion and an impedance portion, and wherein said station network transition detection means includes a detection portion and a communication lead coupling portion, and wherein said detection portion of said station network detection means includes said impedance portion of said hold bridge.
Claim 16
Dependent Claim
21 words
The invention set forth in claim 12 wherein said detection portion of said station network transition detection means is A relay.
Claim 17
Dependent Claim
49 words
The invention set forth in claim 13 wherein said relay has two windings, said windings being connected together in series, said impedance portion of said hold bridge including one of said windings, and said detection portion of said station network transition detection means includes said series connection of windings.
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) | 1978-12-08 | 1979-06-09 | 1979-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-08 | 1983-06-09 | 1983-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-08 | 1987-06-09 | 1987-12-09 | $7700.00 | Window Closed / Lapsed |