1821005

Information

• Patent Grant
• 1821005

• References
• Source

• Patent Number

  1,821,005

• Date Filed

  Not available

• Date Issued

  Tuesday, September 1, 1931
  93 years ago

• CPC

  • H04B1/60 - Supervising unattended repeaters

• US Classifications

  • 330 - Amplifiers
  • 379 - Telephonic communications