3654605

Information

• Patent Grant
• 3654605

• References
• Source

• Patent Number

  3,654,605

• Date Filed

  Not available

• Date Issued

  Tuesday, April 4, 1972
  52 years ago

• CPC

  • H04Q9/08 - Calling by using continuous ac
  • G08C19/14 - using combination of fixed frequencies

• US Classifications

  • 340 - Communications: electrical