3428750

Information

• Patent Grant
• 3428750

• References
• Source

• Patent Number

  3,428,750

• Date Filed

  Not available

• Date Issued

  Tuesday, February 18, 1969
  55 years ago

• CPC

  • G08B27/006 - with transmission via telephone network
  • H04Q5/08 - Signalling by continuous ac

• US Classifications

  • 379 - Telephonic communications
  • 340 - Communications: electrical