3397288

Information

• Patent Grant
• 3397288

• References
• Source

• Patent Number

  3,397,288

• Date Filed

  Not available

• Date Issued

  Tuesday, August 13, 1968
  56 years ago

• CPC

  • H04M19/04 - ringing-current generated at substation
  • H04M3/64 - Arrangements for signalling the number or class of the calling line to the operator

• US Classifications

  • 379 - Telephonic communications