Patent US2519555A successfully refreshed from Google Patents.
Patent US3156781A successfully refreshed from Google Patents.
US3156781A
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US
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Called-line tone-signaling system
Assignee: TDK Micronas GmbH
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Filing: 1960-08-05
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Granted: 1964-11-10
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Expires: 1980-08-05
Abstract
No abstract record available.
Inventors
- 👤 Paul W Hemminger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:34
CPC Classifications
H; H04; H04Q; H04Q3/00
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
69 words
A TELEPHONE SYSTEM COMPRISING A PLURALITY OF SUBSCRIBER LINES, AN AUTOMATIC SWITCHING NETWORK INCLUDING A PLURALITY OF CONNECTING MEANS FOR SELECTIVELY INTERCONNECTING SAID LINES TO COMPLETE PATHS BETWEEN CALLING AND CALLED LINES, MEANS FOR BUSY MARKING BOTH SAID CALLING AND CALLED LINES TO GUARD AGAINST DOUBLE SEIZURE, MEANS RESPONSIVE TO A CALL TO A BUSY LINE FOR APPLYING A DISTINCTIVE CALL SIGNAL TO SAID BUSY LINE WHILE PRECLUDING THE
Claim 2
Dependent Claim
69 words
A TELEPHONE SYSTEM COMPRISING A PLURALITY OF SUBSCRIBER LINES, AN AUTOMATIC SWITCHING NETWORK INCLUDING A PLURALITY OF CONNECTING MEANS FOR SELECTIVELY INTERCONNECTING SAID LINES TO COMPLETE PATHS BETWEEN CALLING AND CALLED LINES, MEANS FOR BUSY MARKING BOTH SAID CALLING AND CALLED LINES TO GUARD AGAINST DOUBLE SEIZURE, MEANS RESPONSIVE TO A CALL TO A BUSY LINE FOR APPLYING A DISTINCTIVE CALL SIGNAL TO SAID BUSY LINE WHILE PRECLUDING THE
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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) | 1967-11-10 | 1968-05-11 | 1968-11-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1971-11-10 | 1972-05-11 | 1972-11-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1975-11-10 | 1976-05-11 | 1976-11-10 | $7700.00 | Window Closed / Lapsed |