Category:A system of multiplex telephony by the use of vacuum tubes (1919)

Media in category "A system of multiplex telephony by the use of vacuum tubes (1919)"

The following 7 files are in this category, out of 7 total.

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  A system of multiplex telephony by the use of vacuum tubes (1919) (14586568667).jpg 3,088 × 2,170; 714 KB
  
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  A system of multiplex telephony by the use of vacuum tubes (1919) (14750051916).jpg 3,088 × 2,170; 457 KB
  
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  A system of multiplex telephony by the use of vacuum tubes (1919) (14769879931).jpg 3,088 × 2,170; 810 KB
  
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  A system of multiplex telephony by the use of vacuum tubes (1919) (14769888451).jpg 3,088 × 2,170; 895 KB
  
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  A system of multiplex telephony by the use of vacuum tubes (1919) (14770693334).jpg 3,088 × 2,170; 586 KB
  
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  A system of multiplex telephony by the use of vacuum tubes (1919) (14773049625).jpg 2,170 × 3,100; 662 KB
  
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  A system of multiplex telephony by the use of vacuum tubes (IA systemofmultiple00arno).pdf 1,218 × 1,675, 156 pages; 4.05 MB