US3916381A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Loop arrangement to test a remote subscriber{3 s drop from a central office via a PCM subscriber carrier system
Assignee: Nokia of America Corp
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Filing: 1974-09-18
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Granted: 1975-10-28
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Expires: 1994-09-18
Abstract
Abstract The tests to be carried out are initiated at the central office by setting a test flip-flop which couples a test signal to the digital system. The test signal starts the subscriber end of the arrangement by activating a clock which clocks a divider chain which in turn drives two relays in the proper sequence to sequentially test the subscriber''s drop for a ground to either of the tip or ring conductors, a short between the tip and ring conductors and a foreign battery coupled to either of the tip or ring conductors. The relays connect the tip and ring conductors of the drop under test to the proper one of two tandem connected low pass filter and comparator circuits. Drop test logic stores the results of the individual test and applies them to the digital system for reporting back to the central office. When the results on the digital system are received at the central office, the test results are visually displayed. When the subscriber end finishes sending the test results, and end of test reset circuit resets the test flip-flop ending the test.
Inventors
- 👤 Iii Lehman Holson Johnson
- 👤 Thomas Paul Maryscuk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 00:30
CPC Classifications
H; H04; H04M; H04M3/00; H04M3/22; H04M3/26; H04M3/28; H04M3/30; H04M3/302; H04M3/303; H04M3/301
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
275 words
A looped test arrangement connected to a digital subscriber carrier system operating during the synchronization time of said digital system to test from a central office a remote subscriber''s drop including ring and tip conductors for a ground condition on either of said ring and tip conductors, a short condition between said ring and tip conductors, a foreign battery condition on either of said ring or tip conductors, or a no fault condition comprising: said central office including first means coupled to said digital system to apply a test signal to said digital system for transmission to said remote subscriber''s end of said digital system, and second means coupled to said digital system to receive signals indicative of said conditions of said drop and to display said conditions of said drop; and subscriber equipment at said remote subscriber''s end of said digital system including third means coupled to said digital system responsive to said test signal to generate different sequential clock signals to enable sequential testing of said drop for said ground condition, said short condition and said foreign battery condition, fourth means coupled to said drop, said third means and said digital system responsive to said sequential clock signals to sequentially test said drop for said ground condition, said short condition and said foreign battery condition and to transmit a binary level indicative of the condition of said drop on said digital system to said second means, and fifth means coupled to said fourth means and said digital system to detect a no fault condition in said fourth means and to transmit a no fault indication on said digital system to said second means.
Claim 2
Dependent Claim
275 words
A looped test arrangement connected to a digital subscriber carrier system operating during the synchronization time of said digital system to test from a central office a remote subscriber''s drop including ring and tip conductors for a ground condition on either of said ring and tip conductors, a short condition between said ring and tip conductors, a foreign battery condition on either of said ring or tip conductors, or a no fault condition comprising: said central office including first means coupled to said digital system to apply a test signal to said digital system for transmission to said remote subscriber''s end of said digital system, and second means coupled to said digital system to receive signals indicative of said conditions of said drop and to display said conditions of said drop; and subscriber equipment at said remote subscriber''s end of said digital system including third means coupled to said digital system responsive to said test signal to generate different sequential clock signals to enable sequential testing of said drop for said ground condition, said short condition and said foreign battery condition, fourth means coupled to said drop, said third means and said digital system responsive to said sequential clock signals to sequentially test said drop for said ground condition, said short condition and said foreign battery condition and to transmit a binary level indicative of the condition of said drop on said digital system to said second means, and fifth means coupled to said fourth means and said digital system to detect a no fault condition in said fourth means and to transmit a no fault indication on said digital system to said second means.
Claim 3
Dependent Claim
33 words
An arrangement according to claim 1, wherein said first means includes a flip-flop coupled to said digital system to provide a binary 1 for a predetermined length of time as said test signal.
Claim 4
Dependent Claim
42 words
An arrangement according to claim 1, wherein said second means includes a display coupled to said digital system to display said conditions of said drop, and a reset circuit coupled between said display and said first means to terminate said test signal.
Claim 5
Dependent Claim
20 words
An arrangement according to claim 3, wherein said display includes four light emitting diodes, one for each of said conditions.
Claim 6
Dependent Claim
20 words
An arrangement according to claim 4, wherein said reset circuit includes a NOR gate coupled to each of said diodes.
Claim 7
Dependent Claim
57 words
An arrangement according to claim 1, wherein said third means includes a clock coupled to said digital system activated by said test signal, a three stage binary counter coupled to said clock, a one shot circuit coupled to said clock, and a decoder coupled to said counter and said one shot circuit to generate said clock signals.
Claim 8
Dependent Claim
265 words
An arrangement according to claim 1, wherein said fourth means includes a first relay coupled to said third means controlled by a first of said clock signals, a second relay coupled to said third means controlled by a second of said clock signals, a switching arrangement coupled to said ring and tip conductors controlled by said first and second relays, a first low pass filter coupled to said switching arrangement, a minus comparator coupled to said first filter, a second low pass filter coupled to said switching arrangement, a plus comparator coupled to said second filter, said first and second filters being coupled to said ring and tip conductors through said switching arrangement depending upon the test being performed, a first storage device coupled to said third means controlled by a third of said clock signals selectively coupled to said minus and plus comparators by said first and second relays to store said ground condition, a second storage device coupled to said third means controlled by a fourth of said clock signals selectively coupled to said minus and plus comparators by said first and second relays to store said short conditions, a third storage device coupled to said third means controlled by a fifth of said clock signals selectively coupled to said minus and plus comparators by said first and second relays to store said foreign battery condition, and first logic circuitry coupled to said third means and each of said first, second and third storage devices to read the contents of each of said first, second and third storage devices into said PCM system.
Claim 9
Dependent Claim
53 words
An arrangement according to claim 7, wherein said fifth means includes second logic circuitry coupled to said third means and each of said first, second and third storage devices to provide a no fault signal when there is a no fault condition stored in each of said first, second and third storage devices.
Claim 10
Dependent Claim
45 words
An arrangement according to claim 1, wherein said fifth means includes logic circuitry coupled to said third means and said fourth means to provide a no fault signal when there is a no fault condition for each of said ground, short and foreign battery tests.
Claim 11
Dependent Claim
451 words
An arrangement according to claim 1, wherein said first means includes a flip-flop coupled to said digital system to provide a binary 1 for a predetermined length of time as said test signal; said second means includes a display coupled to said digital system to display said conditions of said drop, and a reset circuit coupled between said display and said first means to terminate said test signal; said display includes four light emitting diodes, one for each of said conditions; said reset circuit includes a NOR gate coupled to each of said diodes; said third means includes a clock coupled to said digital system activated by said test signal, a three stage binary counter coupled to said clock, a one shot circuit coupled to said clock, and a decoder coupled to said counter and said one shot circuit to generate said clock signals; said fourth means includes a first relay coupled to said decoder controlled by a first of said clock signals, a second relay coupled to said third means controlled by a second of said clock signals, a switching arrangement coupled to said ring and tip conductors controlled by said first and second relays, a first low pass filter coupled to said switching arrangement, a minus comparator coupled to said first filter, a second lOw pass filter coupled to said switching arrangement, a plus comparator coupled to said second filter, said first and second filters being coupled to said ring and tip conductors through said switching arrangement depending upon the test being performed, a first storage device coupled to said decoder controlled by a third of said clock signals selectively coupled to said minus and plus comparators by said first and second relays to store said ground condition, a second storage device coupled to said decoder controlled by a fourth of said clock signals selectively coupled to said minus and plus comparators by said first and second relays to store said short conditions, a third storage device coupled to said decoder controlled by a fifth of said clock signals selectively coupled to said minus and plus comparators by said first and second relays to store said foreign battery condition, and first logic circuitry coupled to the last stage of said counter and each of said first, second and third storage devices to read the contents of each of said first, second and third storage devices into said digital system; and said fifth means includes second logic circuitry coupled to the last stage of said counter and each of said first, second and third storage devices to provide a no fault signal when there is a no fault condition stored in each of said first, second and third storage devices.
References Cited (Backward Citations)
US3770912A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |