US4010332A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Link circuit for intercom unit
Assignee: U S Holding Co Inc
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Filing: 1975-08-11
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Granted: 1977-03-01
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Expires: 1995-08-11
Abstract
Abstract An intercommunication link for a multiple link key telephone system with a combination lamp-button on each handset for each available link. In each link, a line seeking intercom service is sensed to operate a relay in the link selected. A lamp flash signal on the lamp of the selected link is initiated. In this condition, all other links are disabled and none can be accessed when one link is in the lamp flashing condition. The called local number of the desired intercom station is dialed and when the called station line is answered, a second relay in the selected link operates to release the first relay. On operation of the second relay, a steady lamp indication is sent to both stations in the conversation. Other free links may be accessed at this time. Thus, only during this intercom signaling phase are the remaining free links affected.
Inventors
- 👤 Coy Edwin Matheny
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:36
CPC Classifications
H; H04; H04M; H04M9/00; H04M9/002
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
126 words
An intercom circuit including a plurality of link circuits for controlling supervisory signalling between respective calling and called station pairs, each link circuit including a first relay, the first relay in one link circuit responsive to a calling station signalling a called station to attempt the completion of an intercom call over said one link circuit between said stations, means in said one link circuit responsive to operation of said first relay in said one link circuit for disabling the first relays in each of the remaining link circuits from operating during the pendency of operation of said first relay, and means in said one link circuit operated on completion of said intercom call for causing restoration of said first relay of said one link circuit.
Claim 2
Dependent Claim
126 words
An intercom circuit including a plurality of link circuits for controlling supervisory signalling between respective calling and called station pairs, each link circuit including a first relay, the first relay in one link circuit responsive to a calling station signalling a called station to attempt the completion of an intercom call over said one link circuit between said stations, means in said one link circuit responsive to operation of said first relay in said one link circuit for disabling the first relays in each of the remaining link circuits from operating during the pendency of operation of said first relay, and means in said one link circuit operated on completion of said intercom call for causing restoration of said first relay of said one link circuit.
Claim 3
Dependent Claim
70 words
An intercom circuit as claimed in claim 1, wherein there is a second relay in each link circuit, the second relay of said one link circuit operated responsive to the completion of said intercom call by the called party in response to operation of said restoring means for restoring the first relay in the same link circuit and to terminate the disabling of first relays in the remaining link circuits.
Claim 4
Dependent Claim
38 words
An intercom circuit as claimed in claim 2, wherein there is an operating path to said second relay in each link circuit, said operating path being unaffected by operation of a first relay in any other link circuit.
Claim 5
Dependent Claim
56 words
An intercom circuit as claimed in claim 3, wherein the operating path in each link circuit includes the restoring means for that link circuit, each restoring means comprising a two output latch circuit with one output feeding the second relay for that link circuit and the other output feeding the first relay of that link circuit.
Claim 6
Dependent Claim
145 words
An intercom link circuit for supervising the condition of a call between a calling station and a called station, comprising means responsive to said calling station going off-hook for enabling said link circuit, a bistable circuit responsive to said calling station going off-hook for switching to a first condition, a first relay operated responsive to said bistable circuit switching to said first condition for enabling dialing from said calling station, said bistable circuit responsive to said called station going off-hook for switching to a second condition, a second relay operated when said bistable circuit is in said second condition, said first relay restoring responsive to said bistable circuit switching to said second condition, and means responsive to said first relay remaining operated for a predetermined interval for switching said bistable circuit to said second condition to operate said second relay and restore said first relay.
Claim 7
Dependent Claim
145 words
An intercom link circuit for supervising the condition of a call between a calling station and a called station, comprising means responsive to said calling station going off-hook for enabling said link circuit, a bistable circuit responsive to said calling station going off-hook for switching to a first condition, a first relay operated responsive to said bistable circuit switching to said first condition for enabling dialing from said calling station, said bistable circuit responsive to said called station going off-hook for switching to a second condition, a second relay operated when said bistable circuit is in said second condition, said first relay restoring responsive to said bistable circuit switching to said second condition, and means responsive to said first relay remaining operated for a predetermined interval for switching said bistable circuit to said second condition to operate said second relay and restore said first relay.
Claim 8
Dependent Claim
56 words
A link circuit as claimed in claim 5, wherein there is means for sensing the current fed to said link circuit responsive to said calling station going off-hook for operating said first relay, said current sensing means responsive to said called station going off-hook for feeding current to said link circuit for operating said second relay.
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) | 1980-02-29 | 1980-08-30 | 1981-03-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-02-29 | 1984-08-30 | 1985-03-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-02-29 | 1988-08-30 | 1989-03-01 | $7700.00 | Window Closed / Lapsed |