3873921

Information

• Patent Grant
• 3873921

• References
• Source

• Patent Number

  3,873,921

• Date Filed

  Not available

• Date Issued

  Tuesday, March 25, 1975
  49 years ago

• CPC

  • G04C21/28 - by closing a contact to put into action electro-acoustic means
  • H03G1/0088 - using discontinuously variable devices

• US Classifications

  • 455 - Telecommunications
  • 340 - Communications: electrical
  • 968 - Horology