US3742450A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Isolating power supply for communication loop
Assignee: AT&T Inc
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Filing: 1972-07-14
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Granted: 1973-06-26
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Expires: 1992-07-14
Abstract
Abstract An isolating power supply having direct-current power as its input and providing a direct-current output having a ground that is independent of the input power lines.
Inventors
- 👤 D Weller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:05
CPC Classifications
H; H02; H02M; H02M3/00; G; G05; G05F; G05F3/00; G05F3/02; G05F3/08; G05F3/10; G05F3/16; G05F3/18; G05F3/20; G05F3/22; G05F3/222; G05F3/227; H04; H04B; H04B3/00; H04B3/02; H04B3/44; H04L; H04L12/00; H04L12/28; H04L12/42
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
78 words
A loop communication system comprising: a central control; a communication loop attached to said central control; a power loop attached to said central control; and at least one local station connected to both of said loops comprising means for transferring information to and from said communication loop, and a direct-coupled circuit for each local station to derive from said power loop a DC voltage supply having a ground potential independent of the grounds of all other local stations.
Claim 2
Dependent Claim
78 words
A loop communication system comprising: a central control; a communication loop attached to said central control; a power loop attached to said central control; and at least one local station connected to both of said loops comprising means for transferring information to and from said communication loop, and a direct-coupled circuit for each local station to derive from said power loop a DC voltage supply having a ground potential independent of the grounds of all other local stations.
Claim 3
Dependent Claim
83 words
A loop communication system comprising: a central control; a communication loop attached to said central control; a power loop attached to said central control; and at least one local station attached to both of said loops comprising a user device, means for transferring information between said communication loop and said user device, and a direct-coupled circuit for each local station to derive from said power loop a DC voltage supply having a ground potential independent of the grounds of all other local stations.
Claim 4
Dependent Claim
83 words
A loop communication system comprising: a central control; a communication loop attached to said central control; a power loop attached to said central control; and at least one local station attached to both of said loops comprising a user device, means for transferring information between said communication loop and said user device, and a direct-coupled circuit for each local station to derive from said power loop a DC voltage supply having a ground potential independent of the grounds of all other local stations.
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) | 1976-06-25 | 1976-12-25 | 1977-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-25 | 1980-12-25 | 1981-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-25 | 1984-12-25 | 1985-06-26 | $7700.00 | Window Closed / Lapsed |