Patent US4536621A successfully refreshed from Google Patents.
US4536621A
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Dual talk path key telephone
Assignee: Morgan Stanley Senior Funding Inc
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Filing: 1984-05-08
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Granted: 1985-08-20
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Expires: 2004-05-08
Abstract
Abstract In a multiple talk path key telephone of the type of having multiple handsets, each handset is coupled to the key field for a predetermined short period of time when it is initially taken "off hook". During this predetermined time period a user can depress a key and connect with a desired telephone line. If the user has the handset "off hook" and desires to connect to another telephone line, he merely depresses an access key and the handset is again reconnected to the key field for the predetermined time period. The present invention eliminates the possibility of one user disconnecting another user's telephone line during a telephone conversation.
Inventors
- 👤 Henry M. Bergen
- 👤 Sedat Zaimi
- 👤 Vincenzo Castellano
- 👤 Irwin Schildkraut
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:27
CPC Classifications
H; H04; H04M; H04M9/00; H04M9/002; H04M1/00; H04M1/02; H04M1/0289; H04M1/71; H04M1/715
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
78 words
In a multi-line key telephone system the combination of: a key field including a plurality of non-locking pushbutton keys for selected line connections; at least two independent audio terminations; means for coupling said key field to control line selection for a particular audio termination only for a predetermined interval after a new line request therefor; and switching means for coupling said audio terminations to a selected line if selected during said predetermined interval following a new line request.
Claim 2
Dependent Claim
78 words
In a multi-line key telephone system the combination of: a key field including a plurality of non-locking pushbutton keys for selected line connections; at least two independent audio terminations; means for coupling said key field to control line selection for a particular audio termination only for a predetermined interval after a new line request therefor; and switching means for coupling said audio terminations to a selected line if selected during said predetermined interval following a new line request.
Claim 3
Dependent Claim
14 words
The system according to claim 1 wherein said independent audio terminations are independent handsets.
Claim 4
Dependent Claim
30 words
The system according to claim 2 wherein a new line request is initiated either by taking a handset off-hook or by actuating an access key if a handset is off-hook.
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) | 1988-08-19 | 1989-02-18 | 1989-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-08-19 | 1993-02-18 | 1993-08-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-08-19 | 1997-02-18 | 1997-08-20 | $7700.00 | Window Closed / Lapsed |