Patent US3573371A successfully refreshed from Google Patents.
US3573371A
Expired / Lapsed
US
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Direct-current data set arranged for polar signaling and full duplex operation
Assignee: AT&T Inc
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Filing: 1968-12-23
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Granted: 1971-04-06
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Expires: 1988-12-23
Abstract
Abstract The direction and magnitude of the cumulative polar loop currents on a full duplex two-wire line are monitored by an impedance network which is connected across the signal battery transmitter, the line loop and the line monitor in a manner which enables the monitor to detect incoming marking and spacing currents. The network is arranged to balance or cancel out ground or longitudinal currents that the line loop might apply across the monitor. The application of outgoing signal currents across the monitor is compensated by diodes which alternatively remove or insert impedances in opposing branches of the network when marking or spacing signals are being locally generated.
Inventors
- 👤 John T Carbone
- 👤 George Parker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 21:44
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/08
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
124 words
In a full duplex data set including means for transmitting direct-current signals to a communication line and means for concurrently receiving incoming direct-current signals from said line, said receiving means including a bridge circuit having at least four arms and including a first pair of diagonally opposite terminals connected across the line and a second pair of diagonally opposite terminals connected across the transmitting means and means for detecting the voltage developed across corresponding points in each arm of one pair of opposing arms of said bridge, CHARACTERIZED IN THAT said bridge circuit further includes means controlled by the signals transmitted to the line and independent of the direct-current signals on said line for modifying the impedances of said opposing arms of said bridge.
Claim 2
Dependent Claim
124 words
In a full duplex data set including means for transmitting direct-current signals to a communication line and means for concurrently receiving incoming direct-current signals from said line, said receiving means including a bridge circuit having at least four arms and including a first pair of diagonally opposite terminals connected across the line and a second pair of diagonally opposite terminals connected across the transmitting means and means for detecting the voltage developed across corresponding points in each arm of one pair of opposing arms of said bridge, CHARACTERIZED IN THAT said bridge circuit further includes means controlled by the signals transmitted to the line and independent of the direct-current signals on said line for modifying the impedances of said opposing arms of said bridge.
Claim 3
Dependent Claim
39 words
In a full duplex data set in accordance with claim 1 wherein said controlled means comprises a diode whIch effectively inserts and removes impedances in the detecting means in response to voltage biasing signals developed by the transmitting means.
Claim 4
Dependent Claim
95 words
In a full duplex data set including signal voltage transmitting means for applying current signals to a two-wire line loop and a monitor for recovering incoming signals from the cumulative signal currents on the line loop, said monitor comprising: an impedance network means for d4veloping an output designating the magnitude and direction of current on the line loop; and means responsive to the signal voltage transmitting means and independent of the currents on the line loop for modifying the impedance of the network means to thereby modify the output for each line loop current condition.
Claim 5
Dependent Claim
95 words
In a full duplex data set including signal voltage transmitting means for applying current signals to a two-wire line loop and a monitor for recovering incoming signals from the cumulative signal currents on the line loop, said monitor comprising: an impedance network means for d4veloping an output designating the magnitude and direction of current on the line loop; and means responsive to the signal voltage transmitting means and independent of the currents on the line loop for modifying the impedance of the network means to thereby modify the output for each line loop current condition.
Claim 6
Dependent Claim
34 words
In a full duplex data set in accordance with claim 3 wherein said modifying means comprises a nonlinear impedance device for effectively inserting and removing network impedances in response to signal voltage applied thereto.
Claim 7
Dependent Claim
65 words
In a full duplex data set in accordance with claim 3 wherein said impedance network comprises a first network for detecting the magnitude and direction of current on one wire of the line loop, a second network for detecting the magnitude and direction of current on the other wire of the line loop and means for algebraically combining outputs of the first and second networks.
Claim 8
Dependent Claim
40 words
In a full duplex data set in accordance with claim 5 wherein said modifying means comprises a nonlinear impedance device in each of said first and second networks for effectively inserting and removing network impedances in response to signal voltages.
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) | 1974-04-05 | 1974-10-05 | 1975-04-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-05 | 1978-10-05 | 1979-04-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-05 | 1982-10-05 | 1983-04-06 | $7700.00 | Window Closed / Lapsed |