Patent US3783198A successfully refreshed from Google Patents.
US3783198A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Battery reversal detection
Assignee: AG Communication Systems Corp
•
Filing: 1971-03-18
•
Granted: 1974-01-01
•
Expires: 1991-03-18
Abstract
Abstract Electronic circuitry for detecting battery reversal in telephone control signaling while completely isolating signaling circuits with logic circuits and at the same time interfacing signaling circuits with logic circuits.
Inventors
- 👤 F Couch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:29
CPC Classifications
H; H04; H04Q; H04Q1/00; H04Q1/18; H04Q1/30; H04Q1/38
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
121 words
Apparatus connected to the tip and ring leads of a telephone circuit at a terminating station for detecting the polarity of the local central office battery applied to the telephone circuit leads and for producing a first ouput when the battEry polarity is in a first state, and a second output when the battery polarity is in the other state which comprises: a first diode connected between tip and ring conductors of the telephone circuit; a light-emitting diode connected in parallel opposition across said first diode; and a photo-responsive device disposed in close proximity to said light-emitting diode and connected across a first power supply for switching between conducting and nonconducting states in response to current flow through said light-emitting diode.
Claim 2
Dependent Claim
121 words
Apparatus connected to the tip and ring leads of a telephone circuit at a terminating station for detecting the polarity of the local central office battery applied to the telephone circuit leads and for producing a first ouput when the battEry polarity is in a first state, and a second output when the battery polarity is in the other state which comprises: a first diode connected between tip and ring conductors of the telephone circuit; a light-emitting diode connected in parallel opposition across said first diode; and a photo-responsive device disposed in close proximity to said light-emitting diode and connected across a first power supply for switching between conducting and nonconducting states in response to current flow through said light-emitting diode.
Claim 3
Dependent Claim
62 words
The circuit of claim 1 further defined by an output transistor, a resistor connecting the collector and emitter terminals of said output transistor across a second power supply, means coupling the base of said output transistor to said photo-responsive device for switching said output transistor between cut-off and saturation, and an output terminal connected to said second power supply through said resistor.
Claim 4
Dependent Claim
29 words
The circuit of claim 2 wherein said resistor has a value in relation to the voltage of said second power supply to produce logic signals at said output terminal.
Claim 5
Dependent Claim
37 words
The circuit of claim 2 further defined by said photo-responsive device comprising a phototransistor having the collector thereof directly connected to said first power supply and the emitter resistively coupled to the base of said ouput transistor.
References Cited (Backward Citations)
US2824171A
Cited
US2913532A
Cited
GB884832A
Cited
US3321583A
Cited
FR1513305A
Cited
US3410961A
Cited
US3504127A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-31 | 1977-07-02 | 1978-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-31 | 1981-07-02 | 1982-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-31 | 1985-07-02 | 1986-01-01 | $7700.00 | Window Closed / Lapsed |