US3597550A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Balanced telephone instrument circuit
Assignee: Individual
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Filing: 1968-12-26
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Granted: 1971-08-03
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Expires: 1988-12-26
Abstract
Abstract A balanced telephone circuit includes a microphone connected to the input of a transistor amplifier means having two same-phased outputs and a common output. One of the two same-phased outputs is connected to a first wire of a subscriber''s line. The telephone receiver is connected across the first wire of the subscriber''s line and the other of the same-phased outputs. An artificial load is connected across the other of the same-phased outputs and the second wire of the subscriber''s line which is connected to the common output.
Inventors
- 👤 Olaf Sternbeck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:18
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/58; H04M1/585
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
152 words
A balanced telephone instrument circuit for connection to a subscriber line having at least two wires, said circuit comprising: a microphone for generating voice signals; a transistor amplifier means comprising at least two transistors of the same type, each having a collector terminal, an emitter terminal and a base terminal; means for applying the same-phase of signal fRom said microphone across the base and emitter terminals of said transistors; a common output connected to one wire of said subscriber line; means for connecting the emitter terminals of said transistors to said common output; means for connecting the collector terminal of one of said transistors to the other wire of said subscriber line; a telephone receiver connecting the collector terminal of the other of said transistors to said other wire of said subscriber line; and an artificial load connected between the collector terminal of said other of said transistors and said common output.
Claim 2
Dependent Claim
152 words
A balanced telephone instrument circuit for connection to a subscriber line having at least two wires, said circuit comprising: a microphone for generating voice signals; a transistor amplifier means comprising at least two transistors of the same type, each having a collector terminal, an emitter terminal and a base terminal; means for applying the same-phase of signal fRom said microphone across the base and emitter terminals of said transistors; a common output connected to one wire of said subscriber line; means for connecting the emitter terminals of said transistors to said common output; means for connecting the collector terminal of one of said transistors to the other wire of said subscriber line; a telephone receiver connecting the collector terminal of the other of said transistors to said other wire of said subscriber line; and an artificial load connected between the collector terminal of said other of said transistors and said common output.
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) | 1974-08-02 | 1975-02-01 | 1975-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-02 | 1979-02-01 | 1979-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-02 | 1983-02-01 | 1983-08-03 | $7700.00 | Window Closed / Lapsed |