Patent US3760104A successfully refreshed from Google Patents.
US3760104A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Post pay telephone paystation circuit
Assignee: Nortel Networks Ltd
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Filing: 1972-08-07
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Granted: 1973-09-18
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Expires: 1992-08-07
Abstract
Abstract A telephone paystation which permits normal dialling to, and reception from, a called party without deposition of a coin. When the called party answers, the paystation transmitter circuit is completely disabled by the transmission of reverse battery polarity from the central office to the telephone paystation. Normal transmission is restored, upon deposit of a coin, by turning on a controlled rectifier to complete a low impedance path from the telephone line to the voice transmitter circuit.
Inventors
- 👤 J Critchley
- 👤 R Morrell
- 👤 J Thompson
- 👤 R Hemming
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:35
CPC Classifications
H; H04; H04M; H04M17/00; H04M17/02; H04M17/023
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
258 words
A postpay telephone paystation circuit of the direct current reversing type, comprising: a. a voice transmitter circuit and a voice receiver circuit arranged for connection to a telephone line; b. a first diode in series with the voice transmitter circuit, said diode being poled to pass line current only in the direction resulting from normal line polarity; c. a controlled rectifier connected in parallel with said diode, the anode and the cathode of the controlled rectifier being connected to the cathode and anode of the diode respectively so as to pass current only in the direction resulting from reverse line polarity; d. a coin actuatable momentary transfer switch having normally closed and normally open contacts, the normally open contacts of said switch being arranged to control the gate of the controlled rectifier so as to fire the controlled rectifier upon deposit of a coin when the controlled rectifier is biased in the forward direction by the reverse line polarity; e. a shunt netWork having a selected voltage threshold and adapted to carry current only when the line polarity is reversed, the shunt network being in series with the normally closed contacts of said switch, said network and the normally closed contacts of said switch being in shunt with the telephone line; whereby with reversed line polarity, on the telephone line the voice transmitter circuit is rendered inoperative by the first diode until the controlled rectifier is fired by the deposition of a coin to shunt said diode and thereby permit normal transmission and reception by the telephone paystation.
Claim 2
Dependent Claim
258 words
A postpay telephone paystation circuit of the direct current reversing type, comprising: a. a voice transmitter circuit and a voice receiver circuit arranged for connection to a telephone line; b. a first diode in series with the voice transmitter circuit, said diode being poled to pass line current only in the direction resulting from normal line polarity; c. a controlled rectifier connected in parallel with said diode, the anode and the cathode of the controlled rectifier being connected to the cathode and anode of the diode respectively so as to pass current only in the direction resulting from reverse line polarity; d. a coin actuatable momentary transfer switch having normally closed and normally open contacts, the normally open contacts of said switch being arranged to control the gate of the controlled rectifier so as to fire the controlled rectifier upon deposit of a coin when the controlled rectifier is biased in the forward direction by the reverse line polarity; e. a shunt netWork having a selected voltage threshold and adapted to carry current only when the line polarity is reversed, the shunt network being in series with the normally closed contacts of said switch, said network and the normally closed contacts of said switch being in shunt with the telephone line; whereby with reversed line polarity, on the telephone line the voice transmitter circuit is rendered inoperative by the first diode until the controlled rectifier is fired by the deposition of a coin to shunt said diode and thereby permit normal transmission and reception by the telephone paystation.
Claim 3
Dependent Claim
56 words
The invention 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 are closed.
Claim 4
Dependent Claim
39 words
The invention as claimed in claim 1 wherein the controlled rectifier is fired by connecting a capacitor between the gate and the anode of the controlled rectifier through the normally open contacts of the coin actuatable momentary transfer switch.
Claim 5
Dependent Claim
39 words
The invention as claimed in claim 2 wherein the controlled rectifier is fired by connecting a capacitor between the gate and the anode of the controlled rectifier through the normally open contacts of the coin actuatable momentary transfer switch.
Claim 6
Dependent Claim
54 words
The invention as claimed in claim 1 wherein the shunt network includes second and third diodes poled to carry current resulting from reverse line polarity, and a threshold diode poled to provide a voltage threshold against said reverse line polarity, the threshold diode being in series with, and between, the second and third diodes.
Claim 7
Dependent Claim
54 words
The invention as claimed in claim 2 wherein the shunt network includes second and third diodes poled to carry current resulting from reverse line polarity, and a threshold diode poled to provide a voltage threshold against said reverse line polarity, the threshold diode being in series with, and between, the second and third diodes.
Claim 8
Dependent Claim
27 words
The invention as claimed in claim 2 wherein the attenuation network includes an attenuating resistor connecting the cathode of the threshold diode to the voice receiver circuit.
Claim 9
Dependent Claim
79 words
The invention as claimed in claim 1 wherein the shunt network includes second and third diodes poled to carry current resulting from reverse line polarity and a threshold diode poled to provide a voltage threshold against said reverse line polarity, the threshold diode being in series with, and between, the second and third diodes, and wherein the voltage threshold diode is greater than the voltage across the telephone line at the telephone paystation when the controlled rectifier is conducting.
Claim 10
Dependent Claim
82 words
The invention as claimed in claim 2 wherein the shunt network includes second and third diodes poled to carry current resulting from reverse line polarity and a threshold diode poled to provide a voltage threshold against said reverse line polarity, the threshold diode being in series with, and between, the second and third diodes, and wherein the voltage threshold of the threshold diode is greater than the voltage across the telephone line at the telephone paystation when the controlled rectifier is conducting.
Claim 11
Dependent Claim
127 words
The invention as claimed in claim 2 wherein the controlled rectifier is fired by connecting a capacitor between the gate and the cathode of the controlled rectifier through the normally open contacts of the said transfer switch, wherein the shunt network includes second and third diodes poled to carry current resulting from reverse line polarity and a threshold diode poled to provide a voltage threshold against said reverse polarity, the threshold diode being in series with, and between, the second and third diodes and having a voltage threshold greater than the voltage across the telephone line at the telephone paystation when the controlled rectifier is conducting and wherein the attenUation network includes an attenuating resistor connecting the cathode of the threshold diode to the voice receiver circuit.
Claim 12
Dependent Claim
195 words
A postpay telephone paystation circuit of the direct current reversing type, comprising: a. a voice transmitter circuit and a voice receiver circuit arranged for connection to a telephone line; b. a diode in series with the voice transmitter circuit, said diode being poled to pass current only in the direction resulting from normal line polarity, c. a controlled rectifier connected in parallel with said diode, the anode and the cathode of the controlled rectifier being connected to the cathode and anode of the diode respectively so as to pass current only in the direction resulting from reverse line polarity; d. a coin actuatable momentary contact switch having normally open contacts, said contacts of said switch being arranged to control the gate of the controlled rectifier so as to fire the controlled rectifier upon deposit of a coin when the controlled rectifier is biased in the forward direction by the reverse line polarity; whereby with reversed line polarity, on the telephone line the voice transmitter circuit is rendered inoperative by the diode until the controlled rectifier is fired by deposition of a coin to shunt said diode and thereby permit normal transmission by the telephone paystation.
Claim 13
Dependent Claim
195 words
A postpay telephone paystation circuit of the direct current reversing type, comprising: a. a voice transmitter circuit and a voice receiver circuit arranged for connection to a telephone line; b. a diode in series with the voice transmitter circuit, said diode being poled to pass current only in the direction resulting from normal line polarity, c. a controlled rectifier connected in parallel with said diode, the anode and the cathode of the controlled rectifier being connected to the cathode and anode of the diode respectively so as to pass current only in the direction resulting from reverse line polarity; d. a coin actuatable momentary contact switch having normally open contacts, said contacts of said switch being arranged to control the gate of the controlled rectifier so as to fire the controlled rectifier upon deposit of a coin when the controlled rectifier is biased in the forward direction by the reverse line polarity; whereby with reversed line polarity, on the telephone line the voice transmitter circuit is rendered inoperative by the diode until the controlled rectifier is fired by deposition of a coin to shunt said diode and thereby permit normal transmission by the telephone paystation.
Claim 14
Dependent Claim
39 words
The invention as claimed in claim 11 wherein the controlled rectifier is fired by connecting a capacitor between the gate and the anode of the controlled rectifier through the normally open contacts of the coin actuatable momentary contact switch.
Claim 15
Dependent Claim
27 words
The invention as claimed in claim 11 wherein the voice transmitter circuit includes a transmitter and wherein the controlled rectifier is connected in series with said transmitter.
Claim 16
Dependent Claim
31 words
The invention as defined in claim 12 wherein the voice receiver circuit includes a receiver amplifier and a receiver and wherein the output of said amplifier is connected to the receiver.
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) | 1976-09-17 | 1977-03-19 | 1977-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-17 | 1981-03-19 | 1981-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-17 | 1985-03-19 | 1985-09-18 | $7700.00 | Window Closed / Lapsed |