Patent US3666892A successfully refreshed from Google Patents.
US3666892A
Expired / Lapsed
US
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Speech gate
Assignee: U S Holding Co Inc
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Filing: 1970-05-13
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Granted: 1972-05-30
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Expires: 1990-05-13
Abstract
Abstract An audio frequency gate is disclosed for use in an electronic PABX. In particular, the gate enables the efficient transmission of speech and multi-frequency tones between components which are controlled by dc potentials without disrupting associated dc controls.
Inventors
- 👤 Alfred M Hestad
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 09:21
CPC Classifications
H; H04; H04Q; H04Q3/00; H04Q3/42; H04Q3/52; H04Q3/521
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
98 words
An audio frequency gate for use in transmitting both speech and multi-frequency tones between dc controlled components of an electronic PABX, comprising a constant current source, a current sink, means connecting a diode between a first terminal coupled to said constant current source and a second terminal coupled to said current sink, and first switching means coupled to energize said constant current source and said current sink, causing them to bias the diode to a saturated state, said diode functioning in said saturated state to transmit audio frequency signals in both directions between said first and second terminals.
Claim 2
Dependent Claim
98 words
An audio frequency gate for use in transmitting both speech and multi-frequency tones between dc controlled components of an electronic PABX, comprising a constant current source, a current sink, means connecting a diode between a first terminal coupled to said constant current source and a second terminal coupled to said current sink, and first switching means coupled to energize said constant current source and said current sink, causing them to bias the diode to a saturated state, said diode functioning in said saturated state to transmit audio frequency signals in both directions between said first and second terminals.
Claim 3
Dependent Claim
80 words
An audio frequency gate as claimed in claim 1 including a second constant current source, a second diode, means connecting said second diode between a third terminal coupled to said second constant current source and said second terminal coupled to said current sink, and second switching means for energizing said second constant current source, enabling it to saturate the second diode and enable the second diode to transmit audio frequency signals in both directions between the second and third terminals.
Claim 4
Dependent Claim
80 words
An audio frequency gate as claimed in claim 1 including a third constant current source, a third diode, a register, a fourth terminal means connecting said third constant current source to said third diode and through the diode to said register, and third switching means for energizing said third constant current source, enabling it to saturate the third diode and enable the third diode to transmit audio frequency signals in both directions between the fourth terminal means and said register.
Claim 5
Dependent Claim
38 words
An audio frequency gate as claimed in claim 1, in which dc isolation means are employed to connect said first terminal to a pnpn diode matrix to accept voice frequency signals originating from and going to said matrix.
Claim 6
Dependent Claim
53 words
An audio frequency gate as claimed in claim 2, including a pnpn diode matrix, and dc isolation means employed to connect each of said first and third terminals to respective separate circuits of the pnpn diode matrix to enable two-way voice frequency signals to pass serially through the two circuits of the matrix.
Claim 7
Dependent Claim
38 words
An audio frequency gate as claimed in claim 3 including dc isolation means connecting the third terminal to a pnpn diode matrix, said connections enabling multi-frequency signals to be received through the matrix to and from the register.
Claim 8
Dependent Claim
77 words
An audio frequency gate as claimed in claim 2, including a third constant current source, a third diode, a transfer junctor, fourth terminal means connecting said third constant current source through said third diode to said transfer junctor, and third switching means for energizing said third constant current source, enabling it to saturate the third diode and enable the third diode to transmit audio frequency signals in both directions between the fourth terminal and the transfer junctor.
Claim 9
Dependent Claim
38 words
An audio frequency gate as claimed in claim 7, including dc isolation means connecting the first terminal to a pnpn diode matrix to enable multi-frequency signals to be received through the matrix to and from the transfer junctor.
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) | 1975-05-30 | 1975-11-29 | 1976-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-30 | 1979-11-29 | 1980-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-30 | 1983-11-29 | 1984-05-30 | $7700.00 | Window Closed / Lapsed |