US3728490A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Post pay telephone paystation circuit
Assignee: Nortel Networks Technology Corp
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Filing: 1971-09-07
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Granted: 1973-04-17
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Expires: 1991-09-07
Abstract
Abstract A telephone paystation which permits normal dialing to a called party without prior deposit of a coin. When the called party answers, the paystation transmitter circuit is completely disabled by transmitting reverse battery polarity from the central office to the telephone paystation. Normal operation is restored upon deposit of a coin by turning off a controlled rectifier which previously shunted the telephone line at the paystation.
Inventors
- 👤 J Nowicki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:50
CPC Classifications
H; H04; H04M; H04M17/00; H04M17/02; H04M17/023
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
259 words
A post pay telephone paystation circuit of the direct current reversing type, arranged for connection to a telephone line, said paystation circuit, comprising: a. a telephone station network, said station network having a voice transmitter circuit and a voice receiver circuit; b. a first diode in series with the telephone station network, said diode being poled to pass line current to the voice transmitter circuit only in the direction resulting from normal or non-busy line polarity; c. a first controlled rectifier connected in parallel with said diode, the anode and the cathode of the first controlled rectifier being connected to the cathode and anode of the first diode respectively so as to pass current only in the direction resulting from reversed line polarity; d. a coin actuatable switch having normally closed or break contacts; e. a unidirectional shunt network for conducting line current only when the line polarity is reversed, the shunt network being in series with the normally closed contacts of said switch, said shunt network and normally closed contacts of said switch providing a shunt for the telephone line; f. means for applYing a portion of the line current carried by the shunt network to the gate of the first controlled rectifier to turn on said controlled rectifier when the telephone line polarity is reversed; whereby the voice transmitter circuit is disabled by the application of reverse line polarity until said switch is actuated by a coin deposit to disconnect the shunt network from the telephone line so as to restore transmitter operation at the telephone paystation.
Claim 2
Dependent Claim
259 words
A post pay telephone paystation circuit of the direct current reversing type, arranged for connection to a telephone line, said paystation circuit, comprising: a. a telephone station network, said station network having a voice transmitter circuit and a voice receiver circuit; b. a first diode in series with the telephone station network, said diode being poled to pass line current to the voice transmitter circuit only in the direction resulting from normal or non-busy line polarity; c. a first controlled rectifier connected in parallel with said diode, the anode and the cathode of the first controlled rectifier being connected to the cathode and anode of the first diode respectively so as to pass current only in the direction resulting from reversed line polarity; d. a coin actuatable switch having normally closed or break contacts; e. a unidirectional shunt network for conducting line current only when the line polarity is reversed, the shunt network being in series with the normally closed contacts of said switch, said shunt network and normally closed contacts of said switch providing a shunt for the telephone line; f. means for applYing a portion of the line current carried by the shunt network to the gate of the first controlled rectifier to turn on said controlled rectifier when the telephone line polarity is reversed; whereby the voice transmitter circuit is disabled by the application of reverse line polarity until said switch is actuated by a coin deposit to disconnect the shunt network from the telephone line so as to restore transmitter operation at the telephone paystation.
Claim 3
Dependent Claim
62 words
The postpay telephone paystation circuit as claimed in claim 1 further comprising: an attenuation network connecting the shunt network to the voice receiver circuit to permit a signal on the telephone line to be received by the voice receiver circuit before deposit of a coin, when the telephone line polarity is reversed and the normally closed contacts of said switch are closed.
Claim 4
Dependent Claim
55 words
The invention as claimed in claim 1 wherein the shunt network comprises: a second diode and a second controlled rectifier, poled so as to pass current only in the direction resulting from reversed line polarity, and wherein a selected voltage threshold diode is connected between the gate and the anode of the second controlled rectifier.
Claim 5
Dependent Claim
55 words
The invention as claimed in claim 2 wherein the shunt network comprises: a second diode and a second controlled rectifier, poled so as to pass current only in the direction resulting from reversed line polarity, and wherein a selected voltage threshold diode is connected between the gate and the anode of the second controlled rectifier.
Claim 6
Dependent Claim
93 words
The invention as claimed in claim 1 wherein the shunt network comprises: a second diode and a second controlled rectifier, poled so as to pass current only in the direction resulting from reversed line polarity, the gate and the anode of the second controlled rectifier being joined by a selected voltage threshold diode, and wherein the cathode of the second controlled rectifier is connected to the gate of the first controlled rectifier to apply a portion of the line current carried by the shunt network to the gate of the first controlled rectifier.
Claim 7
Dependent Claim
93 words
The invention as claimed in claim 2 wherein the shunt network comprises: a second diode and a second controlled rectifier, poles so as to pass current only in the direction resulting from reversed line polarity, the gate and the anode of the second controlled rectifier being joined by a selected voltage threshold diode, and wherein the cathode of the second controlled rectifier is connected to the gate of the first controlled rectifier to apply a portion of the line current carried by the shunt network to the gate of the first controlled rectifier.
Claim 8
Dependent Claim
26 words
The invention as defined in claim 4 wherein the attenuation network comprises a capacitor connecting the anode of the second diode to the voice receiver circuit.
Claim 9
Dependent Claim
37 words
The invention as claimed in claim 3 wherein the threshold voltage of the selected voltage threshold diode is greater than the voltage across the telephone line at the telephone paystation when the first controlled rectifier is conducting.
Claim 10
Dependent Claim
37 words
The invention as claimed in claim 5 wherein the threshold voltage of the selected voltage threshold diode is greater than the voltage across the telephone line at the telephone paystation when the first controlled rectifier is conducting.
Claim 11
Dependent Claim
139 words
The invention as claimed in claim 3 wherein the coin actuatable switch includes normally open contacts and wherein the telephone paystation circuit further includes: a third diode in series with the first diode and first controlled rectifier, a third controlled rectifier in parallel with the third diode, the third diode and the third controlled rectifier being poled in the same direction as the first diode and first controlled rectifier respectively; means responsive to closure of the normally open contacts of the coin actuatable switch for turning on the third controlled rectifier; whereby with reversed line polarity, the first and second controlled rectifier conduct to disable the transmitter and receiver circuits and to hold an established call, until a coin deposit turns off the second, and turns on the third controlled rectifier respectively to permit normal receiver and transmitter operation.
Claim 12
Dependent Claim
139 words
The invention as claimed in claim 3 wherein the coin actuatable switch includes normally open contacts and wherein the telephone paystation circuit further includes: a third diode in series with the first diode and first controlled rectifier, a third controlled rectifier in parallel with the third diode, the third diode and the third controlled rectifier being poled in the same direction as the first diode and first controlled rectifier respectively; means responsive to closure of the normally open contacts of the coin actuatable switch for turning on the third controlled rectifier; whereby with reversed line polarity, the first and second controlled rectifier conduct to disable the transmitter and receiver circuits and to hold an established call, until a coin deposit turns off the second, and turns on the third controlled rectifier respectively to permit normal receiver and transmitter operation.
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) | 1976-04-16 | 1976-10-16 | 1977-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-16 | 1980-10-16 | 1981-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-16 | 1984-10-16 | 1985-04-17 | $7700.00 | Window Closed / Lapsed |