Patent US3764752A successfully refreshed from Google Patents.
US3764752A
Expired / Lapsed
US
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Telephone line card system
Assignee: BRAND-REX WILLIMATIC CT
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Filing: 1972-01-11
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Granted: 1973-10-09
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Expires: 1992-01-11
Abstract
Abstract A telephone line card circuit including electrical devices and circuitry for minimizing the electrical components by providing an optical detector for controlling the input to an integrated circuit which in turn controls a multiple function relay operable as a line holding device and a visual and audible signal control device. This circuitry is particularly adapted for use in a key telephone system wherein a plurality of telephone sets are adapted to be selectively connected by an appropriate line key conventionally associated with a hand set, and this line card system includes a delay circuit to preclude dropout of a hold circuit due to line transients or line reversals. When a particular phone is connected to a particular telephone line through a key line button, provision is made for detecting this condition by another integrated circuit which controls a second relay operable for the control of a multiplicity of functions, such as controlling a visual signal for indicating that the circuit is in use, for controlling a line holding bridge, and for controlling the state of the first relay.
Inventors
- 👤 J Yachabach
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:03
CPC Classifications
H; H04; H04M; H04M9/00; H04M9/002; H04M9/005; H04M9/006
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
192 words
In a telephone line circuit having a key system local ringing means, means responsive to a ringing current from a remote location for initiating the operation of said local ringing means, said initiating means including means responsive to said ringing current for emitting light energy by conversion of said ringing current to light energy, means responsive to said light energy for detecting the presence of said light energy, a capacitor, a power source, means including said light detecting means for providing a current conducting circuit to said capacitor from said power source for charging said capacitor to a predetermined threshold voltage, circuit interrupter means including a source of local ringing current, and means responsive to buildup of an electrical charge to said threshold voltage by said capacitor connected for establishing a current path between said interrupter and said local ringing means, said means for establishing a current path comprises an array of integrated circuit gates responsive to said buildup of charge and a pair of relays responsive to said array of gates, said relays having a plurality of contacts which connect said local ringing means to said source of local ringing current.
Claim 2
Dependent Claim
192 words
In a telephone line circuit having a key system local ringing means, means responsive to a ringing current from a remote location for initiating the operation of said local ringing means, said initiating means including means responsive to said ringing current for emitting light energy by conversion of said ringing current to light energy, means responsive to said light energy for detecting the presence of said light energy, a capacitor, a power source, means including said light detecting means for providing a current conducting circuit to said capacitor from said power source for charging said capacitor to a predetermined threshold voltage, circuit interrupter means including a source of local ringing current, and means responsive to buildup of an electrical charge to said threshold voltage by said capacitor connected for establishing a current path between said interrupter and said local ringing means, said means for establishing a current path comprises an array of integrated circuit gates responsive to said buildup of charge and a pair of relays responsive to said array of gates, said relays having a plurality of contacts which connect said local ringing means to said source of local ringing current.
Claim 3
Dependent Claim
24 words
A telephone line circuit as defined in claim 1 wherein said light eNergy conversion means includes a neon lamp and a current limiting resistor.
Claim 4
Dependent Claim
19 words
A telephone line circuit as defined in claim 1 wherein said light detecting means includes a light sensitive resistor.
Claim 5
Dependent Claim
20 words
A telephone line circuit as defined in claim 1 wherein said detecting means comprises a light sensitive solid state device.
Claim 6
Dependent Claim
59 words
A telephone line circuit as defined in claim 1 wherein said means responsive to buildup of an electrical charge to a predetermined threshold level includes an integrated circuit threshold detector, said integrated circuit having a multiple input logic element with an output connected for controlling the establishment of said current path between said interrupter and said local ringing means.
Claim 7
Dependent Claim
114 words
A telephone line circuit as defined in claim 5 including a first and a second multifunction relay each having an operating coil, a first transistor for controlling energization of said first relay coil, one of said integrated circuit inputs to said multiple input logic element being responsive to detection of light by said light detecting means for providing an output controlling said first transistor for energizing said first relay coil in response to ringing current energization of said light emitting means, said first relay having contacts for providing an energizing circuit to said interrupter for establishing said current path, whereby said local ringing means is operatively connected to said source of local ringing current.
Claim 8
Dependent Claim
129 words
A telephone line circuit for a key telephone system having tip and ring lines and including a local subscriber''s telephone line and a telephone set, local ringing means, means connected for response to ringing current from a remote location for initiating the operation of said local ringing means, means connected for response to termination of said ringing current for disabling said local ringing means, means including a hold key for holding said subscriber''s line, and means for indicating at said local line circuit that a subscriber''s line is in use or on hold, a pair of relays, said local ringing initiating means and said holding means each including contacts on said pair of relays, said pair of relays responsive to and energized by an array of integrated circuit gates.
Claim 9
Dependent Claim
129 words
A telephone line circuit for a key telephone system having tip and ring lines and including a local subscriber''s telephone line and a telephone set, local ringing means, means connected for response to ringing current from a remote location for initiating the operation of said local ringing means, means connected for response to termination of said ringing current for disabling said local ringing means, means including a hold key for holding said subscriber''s line, and means for indicating at said local line circuit that a subscriber''s line is in use or on hold, a pair of relays, said local ringing initiating means and said holding means each including contacts on said pair of relays, said pair of relays responsive to and energized by an array of integrated circuit gates.
Claim 10
Dependent Claim
111 words
A telephone line circuit as defined in claim 7, wherein said telephone set has a pickup key, a third relay having an operating coil connected in series with said telephone pickup key, said pair of relays having contacts for connecting said third relay coil in a holding bridge circuit across said tip and ring lines when said telephone set is in off-hook position and said pickup key is closed and for maintaining said holding bridge circuit and third relay coil energized by tip and ring loop current irrespective of subsequent opening of said hold key until a telephone set pickup key is closed or the tip and ring lines are deenergized.
Claim 11
Dependent Claim
50 words
Apparatus as in claim 7 wherein said local ringing means comprises means responsive to said ringing current for emitting light energy by conversion of said ringing current to light energy and means responsive to said light energy for detecting the presence of said light energy to produce an initiating signal.
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) | 1976-10-08 | 1977-04-09 | 1977-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-08 | 1981-04-09 | 1981-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-08 | 1985-04-09 | 1985-10-09 | $7700.00 | Window Closed / Lapsed |