3571522

Information

• Patent Grant
• 3571522

• References
• Source

• Patent Number

  3,571,522

• Date Filed

  Not available

• Date Issued

  Tuesday, March 16, 1971
  54 years ago

• CPC

  • H04L27/1563 - using transition or level detection
  • H04Q1/446 - using one signalling frequency

• US Classifications

  • 370 - Multiplex communications
  • 327 - Miscellaneous active electrical nonlinear devices, circuits, and systems
  • 329 - Demodulators
  • 379 - Telephonic communications