1748858

Information

• Patent Grant
• 1748858

• References
• Source

• Patent Number

  1,748,858

• Date Filed

  Not available

• Date Issued

  Tuesday, February 25, 1930
  95 years ago

• CPC

  • H04R9/042 - by pressurised air

• US Classifications

  • 381 - Electrical audio signal processing systems and devices