US4037058A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Intercom system for a key telephone system
Assignee: U S Holding Co Inc
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Filing: 1976-05-06
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Granted: 1977-07-19
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Expires: 1996-05-06
Abstract
Abstract A control circuit including a mechanical interrupter provides a plurality of interrupted ringing signal bursts when one of a plurality of intercom stations goes off-hook and first initiates a call to another of the plurality of intercom stations. The interrupter also provides an interrupted voltage to cause a button lamp at the another of the plurality of intercom stations to flash. A call selector circuit and a call routing circuit are coupled to the control circuit and the plurality of intercom stations to provide a connection between the one and the another of the plurality of intercom stations to enable the interrupted ringing signal bursts to be conducted on the connection to the another of the plurality of intercom stations. Logic circuitry is coupled to the plurality of intercom stations and the control circuit to detect when the one and the another of the plurality of intercom stations are both off-hook. When this condition is detected the interrupted ringing signal bursts are stopped and the button lamp is caused to glow steadily.
Inventors
- 👤 Robert David Stine
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 05:24
CPC Classifications
H; H04; H04M; H04M9/00; H04M9/002
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
199 words
An intercom system having a plurality of intercom stations comprising: first means to provide a plurality of interrupted ringing signal bursts when one of said plurality of intercom stations goes off-hook and first initiates a call to another of said plurality of intercom stations; second means coupled to said first means and said plurality of intercom stations to provide a connection between said one of said plurality of intercom stations and said another of said plurality of intercom stations, said interrupted ringing signal bursts being conducted on said connection to said another of said intercom stations; and third means coupled to said first means and said plurality of intercom stations to stop said interrupted ringing signal bursts when said another of said plurality of intercom stations goes off-hook; said first means further providing an interrupted voltage for coupling to said other of said plurality of intercom stations to cause a button lamp at said other of said plurality of intercom stations to flash and to provide a steady voltage for coupling to said other of said plurality of intercom stations to cause said button lamp to glow steadily when said other of said plurality of intercom stations goes off-hook.
Claim 2
Dependent Claim
199 words
An intercom system having a plurality of intercom stations comprising: first means to provide a plurality of interrupted ringing signal bursts when one of said plurality of intercom stations goes off-hook and first initiates a call to another of said plurality of intercom stations; second means coupled to said first means and said plurality of intercom stations to provide a connection between said one of said plurality of intercom stations and said another of said plurality of intercom stations, said interrupted ringing signal bursts being conducted on said connection to said another of said intercom stations; and third means coupled to said first means and said plurality of intercom stations to stop said interrupted ringing signal bursts when said another of said plurality of intercom stations goes off-hook; said first means further providing an interrupted voltage for coupling to said other of said plurality of intercom stations to cause a button lamp at said other of said plurality of intercom stations to flash and to provide a steady voltage for coupling to said other of said plurality of intercom stations to cause said button lamp to glow steadily when said other of said plurality of intercom stations goes off-hook.
Claim 3
Dependent Claim
26 words
An intercom system according to claim 1, wherein said first means includes a mechanical interrupter to provide said interrupted ringing signal bursts and said interrupted voltage,
Claim 4
Dependent Claim
94 words
An intercom system according to claim 2, wherein said second means includes a call selector circuit coupled to said first means and said plurality of intercom stations responsive to a call initiating signal identifying said other of said plurality of intercom stations from said one of said plurality of intercom stations to select one of a plurality of output lines; and a call routing circuit coupled to said call selector circuit to connect said one of said plurality of output lines to said another of said plurality of intercom stations to complete said connection.
Claim 5
Dependent Claim
82 words
An intercom system according to claim 3, wherein said call selector circuit includes a selector switch having said plurality of output lines, a stepping magnet means coupled to said selector switch to step said selector switch to said one of said plurality of output lines, said stepping magnet means being controlled by said call initiating signal, and a release magnet coupled to said stepping magnet means to enable said selector switch to return to its initial position when said call is terminated.
Claim 6
Dependent Claim
103 words
An intercom system according to claim 3, wherein said third means includes a first sampling circuit coupled to said plurality of intercom stations, a second sampling circuit coupled to said first sampling circuit, a third sampling circuit coupled to said first sampling circuit and said plurality of intercom stations, and logic circuitry coupled to said first, second and third sampling circuits and said first means to stop said interrupted ringing signal bursts and said interrupted voltage when any one of said first, second and third sampling circuits detects that both said one and said another of said plurality of intercom stations are off-hook.
Claim 7
Dependent Claim
94 words
An intercom system according to claim 1, wherein said second means includes a call selector circuit coupled to said first means and said plurality of intercom stations responsive to a call initiating signal identifying said other of said plurality of intercom stations from said one of said plurality of intercom stations to select one of a plurality of output lines; and a call routing circuit coupled to said call selector circuit to connect said one of said plurality of output lines to said another of said plurality of intercom stations to complete said connection.
Claim 8
Dependent Claim
82 words
An intercom system according to claim 6, wherein said call selector circuit includes a selector switch having said plurality of output lines, a stepping magnet means coupled to said selector switch to step said selector switch to said one of said plurality of output lines, said stepping magnet means being controlled by said call initiating signal, and a release magnet coupled to said stepping magnet means to enable said selector switch to return to its initial position when said call is terminated.
Claim 9
Dependent Claim
103 words
An intercom system according to claim 1, wherein said third means includes a first sampling circuit coupled to said plurality of intercom stations, a second sampling circuit coupled to said first sampling circuit, a third sampling circuit coupled to said first sampling circuit and said plurality of intercom stations, and logic circuitry coupled to said first, second and third sampling circuits and said first means to stop said interrupted ringing signal bursts and said interrupted voltage when any one of said first, second and third sampling circuit detects that both said one and said another of said plurality of intercom stations are off-hook.
Claim 10
Dependent Claim
94 words
An intercom system according to claim 1, wherein said second means includes a call selector circuit coupled to said first means and said plurality of intercom stations responsive to a call initiating signal identifying said other of said plurality of intercom stations from said one of said plurality of intercom stations to select one of a plurality of output lines; and a call routing circuit coupled to said call selector circuit to connect said one of said plurality of output lines to said another of said plurality of intercom stations to complete said connection.
Claim 11
Dependent Claim
82 words
An intercom system according to claim 9, wherein said call selector circuit includes a selector switch having said plurality of output lines, a stepping magnet means coupled to said selector switch to step said selector switch to said one of said plurality of output lines, said stepping magnet means being controlled by said call initiating signal, and a release magnet coupled to said stepping magnet means to enable said selector switch to return to its initial position when said call is terminated.
Claim 12
Dependent Claim
99 words
An intercom system according to claim 9, wherein said third means includes a first sampling circuit coupled to said plurality of intercom stations, a second sampling circuit coupled to said first sampling circuit, a third sampling circuit coupled to said first sampling circuit and said plurality of intercom stations, and logic circuitry coupled to said first, second and third sampling circuits and said first means to stop said interrupted ringing signal bursts when any one of said first, second and third sampling circuits detects that both said one and said another of said plurality of intercom stations are off-hook.
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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) | 1980-07-18 | 1981-01-17 | 1981-07-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-18 | 1985-01-17 | 1985-07-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-18 | 1989-01-17 | 1989-07-19 | $7700.00 | Window Closed / Lapsed |