US3887772A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Signal privacy with safety feature
Assignee: AT&T Inc
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Filing: 1944-06-30
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Granted: 1975-06-03
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Expires: 1964-06-30
Abstract
Abstract 1. In a signal privacy system, a signal current input circuit, a privacy equipment including a source for supplying masking currents thereto, means for combining said masking currents with said signal current for disguising the identity of the signals, a circuit controller having a normal condition and an operated condition, means to impress a portion of said masking currents from said source on said circuit controller, said portion normally having a critical value such as to hold said controller in its normal condition, said circuit controller in its operated condition disabling said signal current input circuit from supplying signal current to said combining means.
Inventors
- 👤 Ralph L Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:58
CPC Classifications
H; H04; H04K; H04K1/00; H04K1/02
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
103 words
In a signal privacy system, a signal current input circuit, a privacy equipment including a source for supplying masking currents thereto, means for combining said masking currents with said signal current for disguising the identity of the signals, a circuit controller having a normal condition and an operated condition, means to impress a portion of said masking currents from said source on said circuit controller, said portion normally having a critical value such as to hold said controller in its normal condition, said circuit controller in its operated condition disabling said signal current input circuit for supplying signal current to said combining means.
Claim 2
Dependent Claim
103 words
In a signal privacy system, a signal current input circuit, a privacy equipment including a source for supplying masking currents thereto, means for combining said masking currents with said signal current for disguising the identity of the signals, a circuit controller having a normal condition and an operated condition, means to impress a portion of said masking currents from said source on said circuit controller, said portion normally having a critical value such as to hold said controller in its normal condition, said circuit controller in its operated condition disabling said signal current input circuit for supplying signal current to said combining means.
Claim 3
Dependent Claim
103 words
In a signal privacy system, a signal current input circuit, a privacy equipment including a source for supplying masking currents thereto, means for combining said masking currents with said signal current for disguising the identity of the signals, a circuit controller having a normal condition and an operated condition, means to impress a portion of said masking currents from said source on said circuit controller, said portion normally having a critical value such as to hold said controller in its normal condition, said circuit controller in its operated condition disabling said signal current input circuit for supplying signal current to said combining means.
Claim 4
Dependent Claim
103 words
In a signal privacy system, a signal current input circuit, a privacy equipment including a source for supplying masking currents thereto, means for combining said masking currents with said signal current for disguising the identity of the signals, a circuit controller having a normal condition and an operated condition, means to impress a portion of said masking currents from said source on said circuit controller, said portion normally having a critical value such as to hold said controller in its normal condition, said circuit controller in its operated condition disabling said signal current input circuit for supplying signal current to said combining means.
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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) | 1978-06-02 | 1978-12-02 | 1979-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-02 | 1982-12-02 | 1983-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-02 | 1986-12-02 | 1987-06-03 | $7700.00 | Window Closed / Lapsed |