US3770898A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Called line status testing circuit
Assignee: AG Communication Systems Corp
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Filing: 1972-06-05
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Granted: 1973-11-06
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Expires: 1992-06-05
Abstract
Abstract A called line status testing circuit for detecting and selectively responding to the status of a called line in a telephone system, the circuit including three relays and means for detecting either (1) an unassigned terminal; (2) an idle terminal; (3) a busy terminal; or (4) a reverting call condition of the called line and selectively operating the three relays to indicate the detected line condition, said detecting and indicating operations being performed simultaneously in a single step.
Inventors
- 👤 J Woodward
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:24
CPC Classifications
H; H04; H04Q; H04Q3/00
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
223 words
A telephone system including an originating line circuit; an originator control lead extending from said originating line circuit; a plurality of called line terminations which may be in any one of the following line conditions- (1) unassinged, (2) idle, (3) busy, or (4) reverting call; a plurality of termination control leads extending respectively from each of said called line terminations; and each said termination control lead being at a predetermined electric potential related to the condition thereof; the improvement comprising called line testing means including circuit means for detecting the potential of said lines at selected terminations and means for coupling said circuit means to said originator control lead and to the termination control lead at said selected termination, said circuit means comprising, first, second and third relay means connectable to the termination control lead at said selected termination for responding to the associated called line condition; said relay means each including respective relay windings; and means coupled respectively to said relay windings for selectively operating said relay means in response to the potential on said called line as follows 2. unassigned-first, second, and third relay means non-operated; 2. idle-first relay means operated, second and third relay means non-operated; 3. busy-second relay means operated, first and third relay means non-operated; and 4. revertive call-second and third relay means operated, first relay means non-operated.
Claim 2
Dependent Claim
223 words
A telephone system including an originating line circuit; an originator control lead extending from said originating line circuit; a plurality of called line terminations which may be in any one of the following line conditions- (1) unassinged, (2) idle, (3) busy, or (4) reverting call; a plurality of termination control leads extending respectively from each of said called line terminations; and each said termination control lead being at a predetermined electric potential related to the condition thereof; the improvement comprising called line testing means including circuit means for detecting the potential of said lines at selected terminations and means for coupling said circuit means to said originator control lead and to the termination control lead at said selected termination, said circuit means comprising, first, second and third relay means connectable to the termination control lead at said selected termination for responding to the associated called line condition; said relay means each including respective relay windings; and means coupled respectively to said relay windings for selectively operating said relay means in response to the potential on said called line as follows 2. unassigned-first, second, and third relay means non-operated; 2. idle-first relay means operated, second and third relay means non-operated; 3. busy-second relay means operated, first and third relay means non-operated; and 4. revertive call-second and third relay means operated, first relay means non-operated.
Claim 3
Dependent Claim
10 words
idle-first relay means operated, second and third relay means non-operated;
Claim 4
Dependent Claim
10 words
idle-first relay means operated, second and third relay means non-operated;
Claim 5
Dependent Claim
7 words
unassigned-first, second, and third relay means non-operated;
Claim 6
Dependent Claim
7 words
unassigned-first, second, and third relay means non-operated;
Claim 7
Dependent Claim
59 words
A telephone system as claimed in claim 1, each of said relay means including resPective lockup relay contacts and lock-up relay windings coupled thereto, said lock-up relay contacts actuable upon operation of the respective relay means in response to the associated line condition (1) through (4) for maintaining said respective relay means operated through said coupled lock-up relay windings.
Claim 8
Dependent Claim
11 words
busy-second relay means operated, first and third relay means non-operated; and
Claim 9
Dependent Claim
11 words
busy-second relay means operated, first and third relay means non-operated; and
Claim 10
Dependent Claim
109 words
A telephone system as claimed in claim 1, wherein said termination control lead is at a negative potential when in said idle condition, and at a positive potential when in said revertive call condition, and said respective means coupled to the relay winding of said first relay means includes a diode, means for connecting said diode in series with said winding to forward bias said diode in response to said called line being in said idle condition for operating said first relay means, and to reverse bias said diode in response to said called line being in said revertive call conditon for preventing operation of said first relay means.
Claim 11
Dependent Claim
99 words
A telephone system as claimed in claim 3 wherein said termination control lead is an open circuit when in said unassigned condition, and said respective means coupled to the relay winding of said third relay means includes a diode, means for connecting said diode in series with said winding to forward bias said diode in response to said called line being in said revertive call condition for operating said third relay means, and to reverse bias said diode in response to said called line being in said unassigned and idle conditions for preventing operation of said third relay means.
Claim 12
Dependent Claim
11 words
revertive call-second and third relay means operated, first relay means non-operated.
Claim 13
Dependent Claim
11 words
revertive call-second and third relay means operated, first relay means non-operated.
Claim 14
Dependent Claim
50 words
A telephone system as claimed in claim 4, wherein said respective means coupled to said first and second relay windings includes impedance means connected in series with said windings for preventing operation of said first and second relay means in response to said called line being in said unassigned condition.
References Cited (Backward Citations)
US1628358A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-05 | 1977-05-07 | 1977-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-05 | 1981-05-07 | 1981-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-05 | 1985-05-07 | 1985-11-06 | $7700.00 | Window Closed / Lapsed |