Patent US3480011A successfully refreshed from Google Patents.
Patent US3939308A successfully refreshed from Google Patents.
US3939308A
Expired / Lapsed
US
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Electronic side of line detector
Assignee: 148074 HOLDINGS CANADA Ltd
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Filing: 1974-09-27
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Granted: 1976-02-17
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Expires: 1994-09-27
Abstract
Abstract A side of line detector with a single operational amplifier with adjustable output. The amplifier input is protected from positive and negative voltage spikes by diodes. Two transistors are coupled to the amplifier to set a comparator voltage reference which allows the rejection of leakage and noise. Test points are provided in the circuit to facilitate testing particular subcircuits and to allow the initial adjustment of the detector.
Inventors
- 👤 David M. Shaver
- 👤 John A. Gauthier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 22:35
CPC Classifications
H; H04; H04Q; H04Q5/00; H04Q5/24
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
173 words
An improved side of line detector for a communication switching system, said system coupled to at least one line including a first and second subscriber loop connected one at a time, said first subscriber loop having a mark impedance coupled to ground, said improved side of line detector comprising: differential amplifier means having at least two inputs for producing an output signal when said two inputs are not equal; input voltage divider means coupled to said line including, first divider means for holding a first input of said amplifier means at a reference voltage, and second divider means for holding a second input of said amplifier means at said reference voltage only when said mark impedance is not connected to said line; comparison output means coupled to said differential amplifier means for producing a side of line signal when said differential amplifier means produces an output signal; whereby only when said first subscriber loop and mark impedance is connected to said line, said comparison output means will produce said side of line signal.
Claim 2
Dependent Claim
173 words
An improved side of line detector for a communication switching system, said system coupled to at least one line including a first and second subscriber loop connected one at a time, said first subscriber loop having a mark impedance coupled to ground, said improved side of line detector comprising: differential amplifier means having at least two inputs for producing an output signal when said two inputs are not equal; input voltage divider means coupled to said line including, first divider means for holding a first input of said amplifier means at a reference voltage, and second divider means for holding a second input of said amplifier means at said reference voltage only when said mark impedance is not connected to said line; comparison output means coupled to said differential amplifier means for producing a side of line signal when said differential amplifier means produces an output signal; whereby only when said first subscriber loop and mark impedance is connected to said line, said comparison output means will produce said side of line signal.
Claim 3
Dependent Claim
21 words
An improved side of line detector as claimed in claim 1 wherein: said differential amplifier means comprises a single operational amplifier.
Claim 4
Dependent Claim
27 words
An improved side of line detector as claimed in claim 1 wherein: said differential amplifier means includes a voltage supply divider network means, including noise suppression means.
Claim 5
Dependent Claim
36 words
An improved side of line detector as claimed in claim 3 further including: voltage spike suppression means coupled to said differential amplifier means; whereby said differential amplifier means is protected from negative and positive voltage spikes.
Claim 6
Dependent Claim
17 words
An improved side of line detector as claimed in claim 3 further including: amplifier output test means.
Claim 7
Dependent Claim
23 words
An improved side of line detector as claimed in claim 1 wherein, said input voltage divider means further includes: amplifier output adjustment means.
Claim 8
Dependent Claim
25 words
An improved side of line detector as claimed in claim 1 wherein, said comparison output means further includes: comparison test means; and transistor output means.
Claim 9
Dependent Claim
46 words
An improved side of line detector as claimed in claim 7 wherein, said transistor output means further includes: leakage reduction means; and noise variation suppression means; whereby only when said first subscriber loop is connected said transistor output means will produce said side of line signal.
Claim 10
Dependent Claim
69 words
An improved side of line detector as claimed in claim 1 wherein: said input voltage divider means further includes; amplifier output adjustment means, said differential amplifier means further includes; voltage supply divider network means, including noise suppression means; amplifier output test means; voltage spike suppression means; and said comparison output means further includes; comparison test means; and transistor output means including, leakage reduction means, and noise variation suppression means.
Claim 11
Dependent Claim
21 words
An improved side of line detector as claimed in claim 9 wherein: said differential amplifier means comprises a single operational amplifier.
References Cited (Backward Citations)
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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) | 1979-02-16 | 1979-08-18 | 1980-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-16 | 1983-08-18 | 1984-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-16 | 1987-08-18 | 1988-02-17 | $7700.00 | Window Closed / Lapsed |