2269692

Information

• Patent Grant
• 2269692

• References
• Source

• Patent Number

  2,269,692

• Date Filed

  Not available

• Date Issued

  Tuesday, January 13, 1942
  83 years ago

• CPC

  • H04M3/40 - Applications of speech amplifiers
  • H04J1/16 - Monitoring arrangements
  • H04Q1/26 - for signalling trouble in unoccupied sub-exchanges

• US Classifications

  • 379 - Telephonic communications
  • 340 - Communications: electrical