using tuning forks or vibrating reeds

Industry

  • CPC
  • H04L25/46
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Patents Grantslast 30 patents

  • Information Patent Grant

    3535450

    • Patent number 3,535,450
    • Issue date Oct 20, 1970
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    2898404

    • Patent number 2,898,404
    • Issue date Aug 4, 1959
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    2239711

    • Patent number 2,239,711
    • Issue date Apr 29, 1941
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    2179690

    • Patent number 2,179,690
    • Issue date Nov 14, 1939
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    2141326

    • Patent number 2,141,326
    • Issue date Dec 27, 1938
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    2118069

    • Patent number 2,118,069
    • Issue date May 24, 1938
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1934364

    • Patent number 1,934,364
    • Issue date Nov 7, 1933
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1873044

    • Patent number 1,873,044
    • Issue date Aug 23, 1932
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1873609

    • Patent number 1,873,609
    • Issue date Aug 23, 1932
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1842722

    • Patent number 1,842,722
    • Issue date Jan 26, 1932
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1804302

    • Patent number 1,804,302
    • Issue date May 5, 1931
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1793700

    • Patent number 1,793,700
    • Issue date Feb 24, 1931
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1758194

    • Patent number 1,758,194
    • Issue date May 13, 1930
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1673726

    • Patent number 1,673,726
    • Issue date Jun 12, 1928
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1579999

    • Patent number 1,579,999
    • Issue date Apr 6, 1926
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1545601

    • Patent number 1,545,601
    • Issue date Jul 14, 1925
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1542860

    • Patent number 1,542,860
    • Issue date Jun 23, 1925
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1542859

    • Patent number 1,542,859
    • Issue date Jun 23, 1925
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1530514

    • Patent number 1,530,514
    • Issue date Mar 24, 1925
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE