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Party line apparatus
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Patent number 4,310,723
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Issue date Jan 12, 1982
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Carl G. Svala
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H04 - ELECTRIC COMMUNICATION TECHNIQUE
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Variable delay ringing detector
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Patent number 4,103,114
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Issue date Jul 25, 1978
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Bell Telephone Laboratories, Incorporated
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Barry Sheldon Bosik
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H04 - ELECTRIC COMMUNICATION TECHNIQUE
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Battery charging circuit
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Patent number 4,048,551
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Issue date Sep 13, 1977
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Bell Telephone Laboratories, Incorporated
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Barry Sheldon Bosik
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H04 - ELECTRIC COMMUNICATION TECHNIQUE
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Electronic side of line detector
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Patent number 3,939,308
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Issue date Feb 17, 1976
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GTE Automatic Electric (Canada) Limited
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David M. Shaver
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H04 - ELECTRIC COMMUNICATION TECHNIQUE
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3927266
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Patent number 3,927,266
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Issue date Dec 16, 1975
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H04 - ELECTRIC COMMUNICATION TECHNIQUE
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3902017
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Patent number 3,902,017
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Issue date Aug 26, 1975
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H04 - ELECTRIC COMMUNICATION TECHNIQUE
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3863036
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Patent number 3,863,036
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Issue date Jan 28, 1975
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H04 - ELECTRIC COMMUNICATION TECHNIQUE
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3700817
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Patent number 3,700,817
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Issue date Oct 24, 1972
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H04 - ELECTRIC COMMUNICATION TECHNIQUE
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3673330
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Patent number 3,673,330
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Issue date Jun 27, 1972
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H04 - ELECTRIC COMMUNICATION TECHNIQUE
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3649778
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Patent number 3,649,778
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Issue date Mar 14, 1972
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H04 - ELECTRIC COMMUNICATION TECHNIQUE
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3639692
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Patent number 3,639,692
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Issue date Feb 1, 1972
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H04 - ELECTRIC COMMUNICATION TECHNIQUE
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3624300
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Patent number 3,624,300
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Issue date Nov 30, 1971
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H04 - ELECTRIC COMMUNICATION TECHNIQUE
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3614323
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Patent number 3,614,323
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Issue date Oct 19, 1971
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H04 - ELECTRIC COMMUNICATION TECHNIQUE
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3588361
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Patent number 3,588,361
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Issue date Jun 28, 1971
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H04 - ELECTRIC COMMUNICATION TECHNIQUE
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3579254
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Patent number 3,579,254
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Issue date May 18, 1971
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H04 - ELECTRIC COMMUNICATION TECHNIQUE
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3530253
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Patent number 3,530,253
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Issue date Sep 22, 1970
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H04 - ELECTRIC COMMUNICATION TECHNIQUE
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3510584
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Patent number 3,510,584
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Issue date May 5, 1970
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H04 - ELECTRIC COMMUNICATION TECHNIQUE
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2957055
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Patent number 2,957,055
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Issue date Oct 18, 1960
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H04 - ELECTRIC COMMUNICATION TECHNIQUE
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2923775
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Patent number 2,923,775
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Issue date Feb 2, 1960
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H04 - ELECTRIC COMMUNICATION TECHNIQUE