3428755

Information

• Patent Grant
• 3428755

• References
• Source

• Patent Number

  3,428,755

• Date Filed

  Not available

• Date Issued

  Tuesday, February 18, 1969
  55 years ago

• CPC

  • H04Q1/4423 - using one signalling frequency
  • H01J1/14 - characterised by the material

• US Classifications

  • 379 - Telephonic communications