US3980837A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for pulsing in telephone sets
Assignee: Telefonaktiebolaget LM Ericsson AB
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Filing: 1975-03-12
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Granted: 1976-09-14
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Expires: 1995-03-12
Abstract
Abstract In a push button operated telephone set to be used in a telephone system designed for break/make impulsing an electronic circuit is used for converting the push button signals to break/make pulse trains. In order to supply power to the electronic circuit from the central battery through the subscriber's line even if the terminal voltage is low at the subscriber, a DC voltage converter is used in the set to multiply the terminal voltage. This converter includes a pulse oscillator which is also used as a timing pulse generator for the electronic circuit, controlling the frequency, make/break ratio and pulse sequence intervals of the dial pulse trains sent to the exchange.
Inventors
- 👤 Lars Erik Jakobsson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:29
CPC Classifications
H; H04; H04M; H04M19/00; H04M19/08; H04M1/00; H04M1/26; H04M1/30; H04M1/31; H04M1/312
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
123 words
Key telephone set for connection to an exchange equipped for dialling by means of sending break pulses through the subscriber's line comprising a telephone instrument with speech transmitting and receiving circuits, a push button dial pad, an electronic circuit for storing the digits dialled on said push buttons and for converting said stored digits to a sequence of dial pulse trains having a pulse frequency, pulse ratio and pulse train as required by the pulse receiving means of the exchange, a DC converter comprising oscillator means and voltage multiplying means having an input connected to the subscriber's line in the hook-off state and an output connected to supply voltage terminals on said electronic circuit, said oscillator supplying timing pulses to said electronic circuit.
Claim 2
Dependent Claim
123 words
Key telephone set for connection to an exchange equipped for dialling by means of sending break pulses through the subscriber's line comprising a telephone instrument with speech transmitting and receiving circuits, a push button dial pad, an electronic circuit for storing the digits dialled on said push buttons and for converting said stored digits to a sequence of dial pulse trains having a pulse frequency, pulse ratio and pulse train as required by the pulse receiving means of the exchange, a DC converter comprising oscillator means and voltage multiplying means having an input connected to the subscriber's line in the hook-off state and an output connected to supply voltage terminals on said electronic circuit, said oscillator supplying timing pulses to said electronic circuit.
Claim 3
Dependent Claim
97 words
A key telephone set as claimed in claim 1 where the electronic circuit has a first output and a second output, said first output being connected on one hand to said transmitting and receiving circuits for disabling them during each of the pulse sequences corresponding to the different digits and on the other hand to said series pass voltage regulator for making it fully conducting, said second output being so connected to the voltage regulator that said regulator is made non conducting during the duration of each of the dial pulses of each of said pulse sequences.
Claim 4
Dependent Claim
87 words
A key telephone set as claimed in claim 3 where a shunt connected voltage regulator is connected across the input of the DC converter, a control input on said shunt connected voltage regulator being connected on one hand to the output of said DC converter and on the other hand to said series pass voltage regulator for activating said shunt connected voltage regulator when said series pass voltage regulator is disabled and for making said shunt connected voltage regulator non conducting during each of said deal pulses.
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) | 1979-09-14 | 1980-03-15 | 1980-09-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-14 | 1984-03-15 | 1984-09-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-14 | 1988-03-15 | 1988-09-14 | $7700.00 | Window Closed / Lapsed |