Patent US3973240A successfully refreshed from Google Patents.
US3973240A
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Power line access data system
Assignee: General Electric Co
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Filing: 1974-12-05
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Granted: 1976-08-03
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Expires: 1994-12-05
Abstract
Abstract A two-way communication system is disclosed utilizing power transmission lines as the transmission medium. The system is a multilevel repeater system in which each repeater has a unique address. The lowest level repeaters poll the terminal stations connected thereto in time multiplex. Transmission over the system is in the form of tone codes, each level preferably utilizing a different set of tones from the next higher or lower level.
Inventors
- 👤 Kouan Fong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:37
CPC Classifications
H; H04; H04B; H04B3/00; H04B3/54; H04B3/58
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
92 words
A two-way communication system utilizing a power transmission network as the medium for transmitting intelligence comprising: a central station; a plurality of terminal stations; a plurality of repeaters interconnecting said central station and said terminal stations in a multi-level, tree-like network; wherein said repeaters are individually addressed and said terminal stations are polled by groups, each said group of terminal stations being coupled to a single repeater at the lowest level of repeaters and said system utilizes tone code signaling in which one tone pattern has priority access to said central station.
Claim 2
Dependent Claim
92 words
A two-way communication system utilizing a power transmission network as the medium for transmitting intelligence comprising: a central station; a plurality of terminal stations; a plurality of repeaters interconnecting said central station and said terminal stations in a multi-level, tree-like network; wherein said repeaters are individually addressed and said terminal stations are polled by groups, each said group of terminal stations being coupled to a single repeater at the lowest level of repeaters and said system utilizes tone code signaling in which one tone pattern has priority access to said central station.
Claim 3
Dependent Claim
57 words
The system as set forth in claim 1 wherein said network comprises a plurality of transmission lines operating at different voltage levels and interconnected by power transformers, wherein said repeaters comprise a pair of couplers for connecting the repeater to the primary and secondary of said power transformers, thereby by-passing the power transformer as a transmission medium.
Claim 4
Dependent Claim
27 words
The system as set forth in claim 2 wherein the terminal stations and the lowest level repeater operate on a tone frequency greater than approximately 15 kHz.
Claim 5
Dependent Claim
68 words
The system as set forth in claim 3 wherein the terminal stations are coupled to the lowest level repeater by a transmission path that includes the interwinding capacitance between the primary and secondary windings of a power distribution transformer, thereby isolating other loads that are fed by different distribution transformers from the path of the tone encoded signals between the terminal stations and lowest level repeater connected thereto.
Claim 6
Dependent Claim
44 words
The system as set forth in claim 1 wherein the lowest level repeaters operate on a tone frequency less than approximately 15 kHz and are coupled to the respective groups of terminal stations by the transformer action of the power distribution transformer located therewith.
Claim 7
Dependent Claim
51 words
The system as set forth in claim 1 wherein each repeater comprises: tone receiving means, and tone generating means coupled to said tone receiving means and actuated thereby; said tone receiving means and tone generating means operating on different sets of frequencies, thereby isolating one level of repeaters from the next.
Claim 8
Dependent Claim
34 words
The two-way communication system as set forth in claim 1 wherein the central station comprises means for responding to a priority signal by establishing a communication path to the source of the priority signal.
Claim 9
Dependent Claim
21 words
The two-way communication system as set forth in claim 7 wherein said terminal stations include means for generating said priority signal.
Claim 10
Dependent Claim
21 words
The two-way communication system as set forth in claim 8 wherein said priority signal is an alarm signal indicating a malfunction.
Claim 11
Dependent Claim
24 words
The two-way communication system as set forth in claim 9 wherein the tone code of said priority signal indicates the nature of the malfunction.
Claim 12
Dependent Claim
45 words
The two-way communication system as set forth in claim 1 wherein said repeaters comprise two sections, the first section operating continuously, the second operating only during the presence of a signal addressed to the particular repeater by the central station or during a priority signal.
Claim 13
Dependent Claim
28 words
The system as set forth in claim 1 wherein at least one of the repeaters is merged with the apparatus at the next higher level in the system.
Claim 14
Dependent Claim
23 words
The system as set forth in claim 12 wherein the repeaters at two different levels are merged and physically located with each other.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-03 | 1980-02-02 | 1980-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-03 | 1984-02-02 | 1984-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-03 | 1988-02-02 | 1988-08-03 | $7700.00 | Window Closed / Lapsed |