1144391

Information

• Patent Grant
• 1144391

• References
• Source

• Patent Number

  1,144,391

• Date Filed

  Not available

• Date Issued

  Tuesday, June 29, 1915
  109 years ago

• CPC

  • H04R21/023 - with more than one granular chamber

• US Classifications

  • 381 - Electrical audio signal processing systems and devices