2224497

Information

• Patent Grant
• 2224497

• References
• Source

• Patent Number

  2,224,497

• Date Filed

  Not available

• Date Issued

  Tuesday, December 10, 1940
  85 years ago

• CPC

  • H04Q5/06 - Signalling by amplitude or polarity of dc
  • H04Q3/00 - Selecting arrangements

• US Classifications

  • 379 - Telephonic communications