US3293370A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Make busy line circuit for key telephone systems
Assignee: AT&T Inc
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Filing: 1963-12-30
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Granted: 1966-12-20
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Expires: 1983-12-30
Abstract
No abstract record available.
Inventors
- 👤 Donald A Macleod
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:42
CPC Classifications
H; H04; H04M; H04M3/00; H04M3/60
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
129 words
A KEY TELEPHONE SYSTEM INCLUDING A PLURALITY OF KEY TELEPHONE STATIONS; RINGING MEANS, SIGNALING MEANS IN SAID STATIONS INCLUDING VISUAL AND AUDIBLE INDICATING MEANS RESPONSIVE TO SAID RINGING MEANS, A FIRST AND A SECOND LINE TERMINATING IN EACH OF SAID STATIONS; A FIRST MEANS RESPONSIVE TO A TERMINATING CALL ON SAID FIRST LINE INCLUDING MEANS FOR MANUALLY ESTABLISHING A CONNECTION TO A CALLED STATION, DETECTOR MEANS INCLUDING RECTIFIER MEANS, TRANSISTOR SWITCH MEANS AND FIRST RELAY MEANS, SAID RECTIFIER MEANS COUPLED TO SAID TRANSISTOR SWITCH MEANS FOR CONTROLLING SAID FIRST RELAY MEANS RESPONSIVE TO SAID RINGING MEANS; A SECOND MEANS RESPONSIVE TO A TERMINATING CALL ON SAID SECOND LINE INCLUDING SWITCHING MATRIX MEANS FOR ESTABLISHING A CONNECTION TO A SECOND LINE ON A CALLED STATION; CALL DIVERTING MEANS FOR TRANS-
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) | 1969-12-19 | 1970-06-20 | 1970-12-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-12-19 | 1974-06-20 | 1974-12-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-12-19 | 1978-06-20 | 1978-12-20 | $7700.00 | Window Closed / Lapsed |