US3838223A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ring trip and dial pulse detection circuit
Assignee: AG Communication Systems Corp
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Filing: 1973-10-01
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Granted: 1974-09-24
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Expires: 1993-10-01
Abstract
Abstract A ring trip and dial pulse detection circuit for use in a private automatic branch exchange (PABX) of the type wherein a pole change ring circuit controls the polarity of the output to the telephone handset. The dial pulse detector portion of the arrangement is optically coupled to the remaining portion of the arrangement, so that it is electrically isolated to minimize interface problems and circuits to a register or controller.
Inventors
- 👤 D Lee
- 👤 Laughlin D Mc
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:10
CPC Classifications
H; H04; H04M; H04M19/00; H04M19/02; H04M19/026; H04M3/00; H04M3/22; H04M3/2272
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
358 words
In a communication system including a pair of line circuits coupled to a junctor via a matrix, said system being a two wire system and each of said line circuits appearing as an inlet on said matrix and said junctor having two ports on the outlet of said matrix, each of said line circuits being coupled with a telephone handset having a dial and ringer and each including a pole change ring circuit for alternately reversing the battery and ground connections to said ringer to energize it, and circuit means for coupling signals including ringing signals to said pole change ring circuit, the improvement comprising an arrangement for detecting dial pulses, said arrangement comprising a first gating means, a second gating means, the output of said first gating means being coupled to said second gating means, a current detector for detecting current flow through said telephone handset and line circuit having an output coupled to said first gating means, the circuit means being coupled to and normally providing a first predetermined signal to said first gating means and to the pole change ring circuit, the latter being operated to connect the battery and ground connections such that current flow through said line circuit and telephone handset when the latter is on-hook is restricted and said current detector is inoperative to couple an output signal to said first gating means, the telephone handset in being off-hook causing current to flow through it and the line circuit, said current detector upon detecting said current flow coupling an output signal to said first gating means, said first gating means responsive to said first predetermined signal coupling an output signal to said second gating means to operate the latter to provide an output signal indicating an on-hook condition and responsive to said first predetermined signal and said output signal from said current detector coupling an output signal to said second gating means to operate the latter to provide an output signal indicating an off-hook condition, whereby dial pulses which are a series of on-hook/ off-hook conditions are detected by said arrangement and electrically duplicated by the output of said second gating means.
Claim 2
Dependent Claim
358 words
In a communication system including a pair of line circuits coupled to a junctor via a matrix, said system being a two wire system and each of said line circuits appearing as an inlet on said matrix and said junctor having two ports on the outlet of said matrix, each of said line circuits being coupled with a telephone handset having a dial and ringer and each including a pole change ring circuit for alternately reversing the battery and ground connections to said ringer to energize it, and circuit means for coupling signals including ringing signals to said pole change ring circuit, the improvement comprising an arrangement for detecting dial pulses, said arrangement comprising a first gating means, a second gating means, the output of said first gating means being coupled to said second gating means, a current detector for detecting current flow through said telephone handset and line circuit having an output coupled to said first gating means, the circuit means being coupled to and normally providing a first predetermined signal to said first gating means and to the pole change ring circuit, the latter being operated to connect the battery and ground connections such that current flow through said line circuit and telephone handset when the latter is on-hook is restricted and said current detector is inoperative to couple an output signal to said first gating means, the telephone handset in being off-hook causing current to flow through it and the line circuit, said current detector upon detecting said current flow coupling an output signal to said first gating means, said first gating means responsive to said first predetermined signal coupling an output signal to said second gating means to operate the latter to provide an output signal indicating an on-hook condition and responsive to said first predetermined signal and said output signal from said current detector coupling an output signal to said second gating means to operate the latter to provide an output signal indicating an off-hook condition, whereby dial pulses which are a series of on-hook/ off-hook conditions are detected by said arrangement and electrically duplicated by the output of said second gating means.
Claim 3
Dependent Claim
50 words
The improvement of claim 1, wherein said current detector comprises a diode and a transistor optically coupled with and operated by said diode, whereby the dial pulse detector portion of said arrangement is electrically isolated so that interface problems and circuits to a register or controller are at a minimum.
Claim 4
Dependent Claim
17 words
The improvement of claim 1, wherein said first and second gating means each comprises a NAND gate.
Claim 5
Dependent Claim
100 words
The improvement of claim 3, wherein said first predetermined signal comprises a logic 1 level signal, said first gating means responsive to said logic 1 level signal coupling a logic 0 level signal to said second gating means to operate the latter to provide a logic 1 level signal output indicating an on-hook condition and responsive to said logic 1 level signal and a logic 1 level signal output from said current detector coupling a logic 0 level signal to said second gating means to operate the latter to provide a logic 0 level signal output indicating an off-hook condition.
Claim 6
Dependent Claim
230 words
The improvement of claim 1, further comprising delay means coupled to said second gating means, a third gating means, said first gating means being coupled to said third gating means, flip-flop means, said first and third gating means being coupled to said flip-flop means for setting and resetting it, a sensing gate for sensing the set and reset state of said flip-flop means coupled to said delay means, the circuit means coupling a ringing signal comprising alternate pulses of a first and a second level to said first, third and sensing gating means and to the pole change ring circuit, the pole change ring circuit being responsive to said first and second level signals to alternately reverse the battery and ground connections to cause and to restrict current flow through the ringer and line circuit, respectively, when said handset is on-hook, said first gating means responsive to said first level signal and an output signal from said current detector enabling said third gating means to reset said flip-flop and responsive to only said first level signal to set said flip-flop, said sensing gate responsive to said second level signal sensing the set and reset state of said flip-flop means and triggering said delay means if said flip-flop means is set, said delay means upon being triggered enabling said second gating means to provide an output signal indicating an on-hook condition.
Claim 7
Dependent Claim
130 words
The improvement of claim 5, wherein said handset in being off-hook permits current flow through the handset and the line circuit which is detected by said current detector, said first gating means being enabled responsive to said first level signal and an output from said current detector upon detecting said current flow to enable said third gating means to reset said flip-flop, whereby said delay means is not triggered by said sensing gate during the following second level signal, said delay means being set to the ring frequency and reverting to its idle state after one ring cycle if it is not triggered by said sensing gate, said delay means upon reverting to its idle state enabling said second gating means to provide an output signal indicating an off-hook condition.
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) | 1977-09-23 | 1978-03-25 | 1978-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-23 | 1982-03-25 | 1982-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-23 | 1986-03-25 | 1986-09-24 | $7700.00 | Window Closed / Lapsed |