1980242

Information

• Patent Grant
• 1980242

• References
• Source

• Patent Number

  1,980,242

• Date Filed

  Not available

• Date Issued

  Tuesday, November 13, 1934
  90 years ago

• CPC

  • H04R13/02 - Telephone receivers

• US Classifications

  • 381 - Electrical audio signal processing systems and devices