3164680

Information

• Patent Grant
• 3164680

• References
• Source

• Patent Number

  3,164,680

• Date Filed

  Not available

• Date Issued

  Tuesday, January 5, 1965
  60 years ago

• CPC

  • H04M1/50 - by generating or selecting currents of predetermined frequencies or combinations of frequencies
  • H04M19/04 - ringing-current generated at substation
  • H04Q1/4465 - the same frequency being used for all signalling information
  • H04Q1/453 - in which m-out-of-n signalling frequencies are transmitted

• US Classifications

  • 379 - Telephonic communications