Patent US3646575A successfully refreshed from Google Patents.
US3646575A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coin-operated apparatus and signalling system
Assignee: International Standard Electric Corp
•
Filing: 1969-12-03
•
Granted: 1972-02-29
•
Expires: 1989-12-03
Abstract
Abstract A telephone pay station central system in which answering of a call originated at the pay station causes the generation of a signal from the central office to the pay station to connect the coil collection and value-indicating network to the line loop. A coin collection relay is thereby energized to collect a coin and to cause a pulse to be returned to the central office indicating that the call can continue. Periodic back-and-forth signalling continues as necessary during the conversation period without disrupting the conversation.
Inventors
- 👤 Edmond Marie Heirbaut
- 👤 Raymond Francis Andrian Fabre
- 👤 Josephus Henricus Karel Camps
- 👤 Michael Marcel Mees
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:29
CPC Classifications
H; H04; H04M; H04M17/00; H04M17/02
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
150 words
Signalling system, for controlling a telephone pay station, comprising a signal receiver network at said station receptive of control signals from a signal transmitter through a DC loaded telephone conversation transmission path, said receiver including an impedance of constant voltage characteristic in series with the low DC impedance input of a said receiver network comprising a transformer connected to prevent a DC couplIng between the transformer input and its output in said transmission path and a bistable device coupled across said impedance of constant voltage characteristic through a normally nonconductive switching transistor, which is operable in response to a pulse output received from said network, and that upon a payment needed, low voltage signal being received by said receiver from said transmitter, said transistor is operated to activate said bistable device by a current flow which is independent of the path loop resistance thereby to implement the collection of payment.
Claim 2
Dependent Claim
150 words
Signalling system, for controlling a telephone pay station, comprising a signal receiver network at said station receptive of control signals from a signal transmitter through a DC loaded telephone conversation transmission path, said receiver including an impedance of constant voltage characteristic in series with the low DC impedance input of a said receiver network comprising a transformer connected to prevent a DC couplIng between the transformer input and its output in said transmission path and a bistable device coupled across said impedance of constant voltage characteristic through a normally nonconductive switching transistor, which is operable in response to a pulse output received from said network, and that upon a payment needed, low voltage signal being received by said receiver from said transmitter, said transistor is operated to activate said bistable device by a current flow which is independent of the path loop resistance thereby to implement the collection of payment.
Claim 3
Dependent Claim
51 words
Signalling system as claimed in claim 1, characterized in this, that said signal from said transmitter is a low-amplitude AC signal of predetermined frequency and duration and is applied to said receiver through two conductors of said line, and means in said network tuned to the frequency of said AC signal.
Claim 4
Dependent Claim
68 words
Signalling system as claimed in claim 2, characterized in this, that said transistor device has a first, a second and a third, electrode, said second and said third electrodes being connected to two ends of said impedance of constant voltage characteristic directly and via said bistable device respectively, said second and said first electrodes being further connected to the output of said network via a rectifying smoothing arrangement.
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) | 1975-02-28 | 1975-08-30 | 1976-02-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-28 | 1979-08-30 | 1980-02-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-28 | 1983-08-30 | 1984-02-29 | $7700.00 | Window Closed / Lapsed |