1897204

Information

• Patent Grant
• 1897204

• References
• Source

• Patent Number

  1,897,204

• Date Filed

  Not available

• Date Issued

  Tuesday, February 14, 1933
  91 years ago

• CPC

  • H04Q9/08 - Calling by using continuous ac

• US Classifications

  • 340 - Communications: electrical
  • 324 - Electricity: measuring and testing