US3840706A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Remote test circuit for carrier telephones
Assignee: SEISCOR Inc
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Filing: 1973-10-29
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Granted: 1974-10-08
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Expires: 1993-10-29
Abstract
Abstract In the preferred embodiment of the invention disclosed herein, a testing circuit is provided in a carrier telephone communication system for determining, from a central office location, the operational status of remote subscriber station terminals. Interrogation of the remote station terminal is accomplished by momentarily reversing the polarity of D.C. voltage applied to the telephone transmission cable. Means are provided at the remote station terminals for detecting the D.C. power voltage reversal and for activating the station terminal transmitter in response thereto. Visual indicating means are provided at the central office for indicating the presence of a carrier signal originated at the station terminal in response to the D.C. voltage reversal.
Inventors
- 👤 L Krasin
- 👤 Callum R Mc
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:06
CPC Classifications
H; H04; H04J; H04J1/00; H04J1/02; H04J1/16; H04Q; H04Q11/00; H04Q11/02
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
106 words
An apparatus for indicating at a central office terminal unit the operative status of a remote carrier telephone station terminal comprising: a switch at the central office terminal unit for reversing polarity of D.C. operating power for the remote station terminal; means at the remote station terminal for detecting the polarity reversal of the operating power and activating a transmitter section of the station terminal in response thereto causing the transmitter section to generate carrier frequency energy; and means within the central office terminal for indicating the presence of station terminal carrier frequency energy and whereby the operative status of the remote station terminal becomes known.
Claim 2
Independent Claim
106 words
An apparatus for indicating at a central office terminal unit the operative status of a remote carrier telephone station terminal comprising: a switch at the central office terminal unit for reversing polarity of D.C. operating power for the remote station terminal; means at the remote station terminal for detecting the polarity reversal of the operating power and activating a transmitter section of the station terminal in response thereto causing the transmitter section to generate carrier frequency energy; and means within the central office terminal for indicating the presence of station terminal carrier frequency energy and whereby the operative status of the remote station terminal becomes known.
Claim 3
Dependent Claim
89 words
An apparatus according to claim 1 wherein the detecting means is a keying transistor interposed between a power supply and a transmitter section and having a connection from said transistor base through a diode to a normally negative one of a pair of transmission wires, said diode having an anode connected to said one transmission wire and a cathode connected to said transistor base such that current flow from said one transmission wire is prevented when said one transmission wire is electrically negative with respect to said transistor base.
Claim 4
Dependent Claim
55 words
An apparatus according to claim 1 wherein the indicating means is a light emitting device having an amplifier transistor for supplying current thereto, said transistor having a base connected to a detector unit such that said amplifier transistor supplies current to said light emitting device whenever carrier frequency energy is received by said detector unit.
Claim 5
Dependent Claim
16 words
An apparatus according to claim 3 wherein the light emitting device is a light emitting diode.
Claim 6
Dependent Claim
92 words
An apparatus according to claim 1 wherein the switch is interposed between a common equipment power supply unit and a two wire transmission line, said switch having a double-pole double-throw configuration and wired such that when the switch is in a normal position, power is supplied to the wires of the transmission line in a first relative electrical polarity and when the switch is in a test position the power supplied to the wires of the transmission line is in a second relative polarity, being the reverse of said first relative polarity.
Claim 7
Independent Claim
84 words
A method of testing the operative status of a remote carrier telephone station terminal from a central office, including the steps of: reversing, at the central office, the relative polarity of D.C. power for operating remote station terminal; detecting at the remote station terminal the reversed polarity and activating a transmitter section of the station terminal to generate carrier frequency energy in response thereto; and indicating, at the central office, thE presence of carrier frequency energy by activating an indicating device in response thereto.
Claim 8
Independent Claim
84 words
A method of testing the operative status of a remote carrier telephone station terminal from a central office, including the steps of: reversing, at the central office, the relative polarity of D.C. power for operating remote station terminal; detecting at the remote station terminal the reversed polarity and activating a transmitter section of the station terminal to generate carrier frequency energy in response thereto; and indicating, at the central office, thE presence of carrier frequency energy by activating an indicating device in response thereto.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-07 | 1978-04-08 | 1978-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-07 | 1982-04-08 | 1982-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-07 | 1986-04-08 | 1986-10-08 | $7700.00 | Window Closed / Lapsed |