US4002860A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transmitting and receiving apparatus
Assignee: NTT Inc
•
Filing: 1975-04-02
•
Granted: 1977-01-11
•
Expires: 1995-04-02
Abstract
Abstract Only one reversible electro-acoustic converter is used to act without a press-to-talk switch or the like as a transmitter and a receiver. The electro-acoustic converter is connected to a communication line through two 2 - 4 converters in the form of hybrid transformers which are interconnected to form a transmitting system and a receiving system.
Inventors
- 👤 Masaaki Terai
- 👤 Kazuhiko Kakehi
- 👤 Ryoichi Matsuda
- 👤 Giichi Ito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:15
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/38; H04B1/40; H04B1/54; H04B1/58; H04M; H04M1/00; H04M1/60; H04M1/6033
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
149 words
Transmitting and receiving apparatus comprising a single reversible electro-acoustic converter acting as a transmitter and a receiver, and first and second 2-wire to 4-wire converters, the 2-wire side terminal pair of said first 2-wire to 4-wire converter being connected to said reversible electro-acoustic converter, the first terminal pair of the 4-wire side terminal pairs of said first 2-wire to 4-wire converter being connected to the first terminal of the 4-wire side terminal pairs of said second 2-wire to 4-wire converter through an amplifier for constituting a transmitting system, the second terminal pair of said 4-wire side terminal pairs of said first 2-wire to 4-wire converter being connected to the second terminal pair of the 4-wire side terminal pairs of said second 2-wire to 4-wire converter for constituting a receiving system, and the 2-wire side terminal pair of said second 2-wire to 4-wire converter being connected to a communication line.
Claim 2
Dependent Claim
149 words
Transmitting and receiving apparatus comprising a single reversible electro-acoustic converter acting as a transmitter and a receiver, and first and second 2-wire to 4-wire converters, the 2-wire side terminal pair of said first 2-wire to 4-wire converter being connected to said reversible electro-acoustic converter, the first terminal pair of the 4-wire side terminal pairs of said first 2-wire to 4-wire converter being connected to the first terminal of the 4-wire side terminal pairs of said second 2-wire to 4-wire converter through an amplifier for constituting a transmitting system, the second terminal pair of said 4-wire side terminal pairs of said first 2-wire to 4-wire converter being connected to the second terminal pair of the 4-wire side terminal pairs of said second 2-wire to 4-wire converter for constituting a receiving system, and the 2-wire side terminal pair of said second 2-wire to 4-wire converter being connected to a communication line.
Claim 3
Dependent Claim
54 words
The transmitting and receiving apparatus according to claim 1 wherein an amplifier is connected in a receiving system extending between the two terminal pair of the 4-wire side terminal pairs of the second 2-wire to 4-wire converter, and the terminal pair of the 4-wire side terminal pairs of said first 2-wire to 4-wire converter.
Claim 4
Dependent Claim
49 words
The transmitting and receiving apparatus according to claim 1 wherein an equalizer for compensating for the frequency characteristic of the transmitted signal is connected between the amplifier in the transmitting system and said first terminal pair of the 4 side terminal pairs of said second 2-wire to 4-wire converter.
Claim 5
Dependent Claim
44 words
The transmitting and receiving apparatus according to claim 1 wherein each 2-wire to 4-wire converter comprises a hybrid transformer, and said first 2-wire to 4-wire converter is connected to a balancing circuit network having an impedance equal to that of said reversible electro-acoustic converter.
Claim 6
Dependent Claim
40 words
The transmitting and receiving apparatus according to claim 4 wherein said second 2-wire to 4-wire converter is connected to a balancing circuit network having an impedance whose value has been set to match with the impedance of a communication line.
Claim 7
Dependent Claim
17 words
The transmitting and receiving apparatus according to claim 5 wherein said communication line comprises a telephone line.
Claim 8
Dependent Claim
45 words
The transmitting and receiving apparatus according to claim 1 wherein a bandpass filter passing only the voice frequencies is connected between said amplifier in the transmitting system and the first terminal pair of the 4 line terminal side of said first 2-wire to 4-wire converter.
Claim 9
Dependent Claim
22 words
The transmitting and receiving apparatus according to claim 1 wherein said first 2-wire to 4-wire converter comprises a bridge type hybrid transformer.
Claim 10
Dependent Claim
20 words
The transmitting and receiving apparatus according to claim 1 wherein said reversible electro-acoustic converter comprises a ear plug type converter.
References Cited (Backward Citations)
US2282465A
Cited
US2535063A
Cited
US2812388A
Cited
US3178648A
Cited
US3889058A
Cited
US3784755A
Cited
US3908095A
Cited
US3778563A
Cited
US3946169A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-01-11 | 1980-07-12 | 1981-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-01-11 | 1984-07-12 | 1985-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-01-11 | 1988-07-12 | 1989-01-11 | $7700.00 | Window Closed / Lapsed |