US3098901A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telephone security system
Assignee: TDK Micronas GmbH
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Filing: 1960-11-17
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Granted: 1963-07-23
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Expires: 1980-11-17
Abstract
No abstract record available.
Inventors
- 👤 Thomas B Norling
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 02:37
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/68; H04M3/00; H04M3/08; H04M3/14
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
108 words
A TELEPHONE SECURITY SYSTEM COMPRISING A PLURALTIY OF MULTI-CONDUCTOR SUBSCRIBER LINES EXTENDING FROM A CENTRAL LOCATION TO REMOTELY LOCATED SUBSCRIBER STATIONS, MEANS AT SAID CENTRAL LOCATION FOR APPLYING A LOW FREQUENCY VOLTAGE, TO A FIRST CONDUCTOR OF EACH OF SAID LINES WHEN IDLE, MEANS CONNECTED TO ANOTHER CONDUCTOR OF EACH OF SAID LINES FOR DETECTING ALTERNATING CURRENT CAUSED BY SAID VOLTAGE WHEN APPLIED TO SAID LINES WHEN A COMPLETE ALTERNATING CURRENT LOOP IS THEN EXTENDED TO AN ASSOCIATED SUBSCRIBER STATION, AND MEANS TRIGGERED RESPONSIVE TO SAID LAST NAMED MEANS DETECTING AN ABSCENCE OF SAID ALTERNATING CURRENT FOR GIVING AN ALARM IF A CALL IS NOT THEN IN PROGRESS.
Claim 2
Dependent Claim
108 words
A TELEPHONE SECURITY SYSTEM COMPRISING A PLURALTIY OF MULTI-CONDUCTOR SUBSCRIBER LINES EXTENDING FROM A CENTRAL LOCATION TO REMOTELY LOCATED SUBSCRIBER STATIONS, MEANS AT SAID CENTRAL LOCATION FOR APPLYING A LOW FREQUENCY VOLTAGE, TO A FIRST CONDUCTOR OF EACH OF SAID LINES WHEN IDLE, MEANS CONNECTED TO ANOTHER CONDUCTOR OF EACH OF SAID LINES FOR DETECTING ALTERNATING CURRENT CAUSED BY SAID VOLTAGE WHEN APPLIED TO SAID LINES WHEN A COMPLETE ALTERNATING CURRENT LOOP IS THEN EXTENDED TO AN ASSOCIATED SUBSCRIBER STATION, AND MEANS TRIGGERED RESPONSIVE TO SAID LAST NAMED MEANS DETECTING AN ABSCENCE OF SAID ALTERNATING CURRENT FOR GIVING AN ALARM IF A CALL IS NOT THEN IN PROGRESS.
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) | 1966-07-22 | 1967-01-21 | 1967-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1970-07-22 | 1971-01-21 | 1971-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1974-07-22 | 1975-01-21 | 1975-07-23 | $7700.00 | Window Closed / Lapsed |