using one signalling frequency

Patents Grantslast 30 patents

  • Information Patent Grant

    Apparatus for selectively enabling subscriber device to respond to...

    • Patent number 5,142,569
    • Issue date Aug 25, 1992
    • Data Accessory Corporation
    • George W. Peters
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    Telephone system with several terminals on a single line

    • Patent number 5,119,418
    • Issue date Jun 2, 1992
    • Dolphin Integration
    • Christian Dupillier
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    AC supervisory signal detector circuit

    • Patent number 4,133,982
    • Issue date Jan 9, 1979
    • GTE Automatic Electric Laboratories Incorporated
    • David Q. Lee
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    Out-of-band signaling method and apparatus to adapt payphones to te...

    • Patent number 4,010,328
    • Issue date Mar 1, 1977
    • The Anaconda Company
    • Ronald F. McGuire
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    3546600

    • Patent number 3,546,600
    • Issue date Dec 8, 1970
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    3546674

    • Patent number 3,546,674
    • Issue date Dec 8, 1970
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    3428755

    • Patent number 3,428,755
    • Issue date Feb 18, 1969
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    3281693

    • Patent number 3,281,693
    • Issue date Oct 25, 1966
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    3200307

    • Patent number 3,200,307
    • Issue date Aug 10, 1965
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    3187234

    • Patent number 3,187,234
    • Issue date Jun 1, 1965
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    3173064

    • Patent number 3,173,064
    • Issue date Mar 9, 1965
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    3060269

    • Patent number 3,060,269
    • Issue date Oct 23, 1962
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    2988600

    • Patent number 2,988,600
    • Issue date Jun 13, 1961
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    2949507

    • Patent number 2,949,507
    • Issue date Aug 16, 1960
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    2941041

    • Patent number 2,941,041
    • Issue date Jun 14, 1960
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    2939391

    • Patent number 2,939,391
    • Issue date Jun 7, 1960
    • F42 - AMMUNITION BLASTING
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    2939919

    • Patent number 2,939,919
    • Issue date Jun 7, 1960
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    2894129

    • Patent number 2,894,129
    • Issue date Jul 7, 1959
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    2892896

    • Patent number 2,892,896
    • Issue date Jun 30, 1959
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    2838613

    • Patent number 2,838,613
    • Issue date Jun 10, 1958
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    2773181

    • Patent number 2,773,181
    • Issue date Dec 4, 1956
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    2754369

    • Patent number 2,754,369
    • Issue date Jul 10, 1956
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    2747175

    • Patent number 2,747,175
    • Issue date May 22, 1956
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    2680784

    • Patent number 2,680,784
    • Issue date Jun 8, 1954
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    2662118

    • Patent number 2,662,118
    • Issue date Dec 8, 1953
    • C10 - PETROLEUM, GAS OR COKE INDUSTRIES TECHNICAL GASES CONTAINING CARBON MON...
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    2657308

    • Patent number 2,657,308
    • Issue date Oct 27, 1953
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    2613274

    • Patent number 2,613,274
    • Issue date Oct 7, 1952
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    2613278

    • Patent number 2,613,278
    • Issue date Oct 7, 1952
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
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    2611062

    • Patent number 2,611,062
    • Issue date Sep 16, 1952
    • C10 - PETROLEUM, GAS OR COKE INDUSTRIES TECHNICAL GASES CONTAINING CARBON MON...
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    2598996

    • Patent number 2,598,996
    • Issue date Jun 3, 1952
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE

Patents Applicationslast 30 patents