1721607

Information

• Patent Grant
• 1721607

• References
• Source

• Patent Number

  1,721,607

• Date Filed

  Not available

• Date Issued

  Tuesday, July 23, 1929
  95 years ago

• CPC

  • H04M5/12 - Ringing or otherwise calling substations
  • H04Q3/42 - Circuit arrangements for indirect selecting controlled by common circuits

• US Classifications

  • 379 - Telephonic communications