3813500

Information

• Patent Grant
• 3813500

• References
• Source

• Patent Number

  3,813,500

• Date Filed

  Not available

• Date Issued

  Tuesday, May 28, 1974
  51 years ago

• CPC

  • H04M17/023 - Circuit arrangements
  • G07F9/02 - Devices for alarm or indication
  • H01B7/32 - with arrangements for indicating defects
  • H02G15/28 - structurally associated with devices for indicating the presence or location of non-electric faults

• US Classifications

  • 379 - Telephonic communications