Name Size Creator Creation Date Labels Comment  
PDF File 1391006.pdf 267 kB Shaun Ewing Sept 20, 1921 00:00
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US-1391006-A // Half-duplex alternating-current telegraph system // Parker Ralzemond D. // American Telephone & Telegraph
PDF File 1390580.pdf 530 kB Shaun Ewing Sept 13, 1921 00:00
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US-1390580-A // Means for reducing interference // Osborne Harold S. // American Telephone & Telegraph
PDF File 1390545.pdf 436 kB Shaun Ewing Sept 13, 1921 00:00
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US-1390545-A // Desk operator's circuits // Rhodes William A. // American Telephone & Telegraph
PDF File 1389596.pdf 450 kB Shaun Ewing Sept 06, 1921 00:00
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US-1389596-A // Desk operator's circuits // Rhodes William A. // American Telephone & Telegraph
PDF File 1386977.pdf 444 kB Shaun Ewing Aug 09, 1921 00:00
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US-1386977-A // Indicating mechanism // Watson Edward F. // American Telephone & Telegraph
PDF File 1385777.pdf 359 kB Shaun Ewing Jul 26, 1921 00:00
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US-1385777-A // Grid-circuits for electron-tubes // Clark Alva B. // American Telephone & Telegraph
PDF File 1384994.pdf 961 kB Shaun Ewing Jul 19, 1921 00:00
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US-1384994-A // Telephone repeater equipment // Demarest Charles S. ; Clark Alva B. ; Crisson George // American Telephone & Telegraph
PDF File 1383750.pdf 1.04 MB Shaun Ewing Jul 05, 1921 00:00
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US-1383750-A // Alternating-current signaling system // Parker Ralzemond D. ; Hamilton Baxter P. // American Telephone & Telegraph
PDF File 1375414.pdf 910 kB Shaun Ewing Apr 19, 1921 00:00
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US-1375414-A // Apparatus for testing capacity deviations and unbalance of electric conductors // Osborne Harold S. // American Telephone & Telegraph
PDF File 1375405.pdf 753 kB Shaun Ewing Apr 19, 1921 00:00
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US-1375405-A // Apparatus for testing capacity of electric conductors // Martin William H. // American Telephone & Telegraph
PDF File 1374219.pdf 460 kB Shaun Ewing Apr 12, 1921 00:00
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US-1374219-A // Composite transmission system // Osborne Harold S. // American Telephone & Telegraph
PDF File 1373504.pdf 363 kB Shaun Ewing Apr 05, 1921 00:00
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US-1373504-A // Electrical measuring apparatus // Hitchcock Harry W. // American Telephone & Telegraph
PDF File 1372838.pdf 398 kB Shaun Ewing Mar 29, 1921 00:00
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US-1372838-A // Pole-derrick // Smith Temple C. // American Telephone & Telegraph
PDF File 1372050.pdf 1.05 MB Shaun Ewing Mar 22, 1921 00:00
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US-1372050-A // Busy-signal-testing apparatus // Toomey John F. // American Telephone & Telegraph
PDF File 1372042.pdf 450 kB Shaun Ewing Mar 22, 1921 00:00
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US-1372042-A // Desk operator's circuits // Rhodes William A. // American Telephone & Telegraph
PDF File 1371298.pdf 347 kB Shaun Ewing Mar 15, 1921 00:00
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US-1371298-A // Telephone and call signal system // Clark Alva B. // American Telephone & Telegraph
PDF File 1370669.pdf 6.70 MB Shaun Ewing Mar 08, 1921 00:00
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US-1370669-A // Machine-telegraph // Potts Louis M. // American Telephone & Telegraph
PDF File 1370562.pdf 419 kB Shaun Ewing Mar 08, 1921 00:00
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US-1370562-A // Trunk-circuits // Shackleton Samuel P. // American Telephone & Telegraph
PDF File 1370558.pdf 441 kB Shaun Ewing Mar 08, 1921 00:00
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US-1370558-A // Machine ringing system // Rhodes William A. // American Telephone & Telegraph
PDF File 1369828.pdf 315 kB Shaun Ewing Mar 01, 1921 00:00
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US-1369828-A // Cable-hanger // Matthews Edgar M. // American Telephone & Telegraph
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