2838613

Information

• Patent Grant
• 2838613

• References
• Source

• Patent Number

  2,838,613

• Date Filed

  Not available

• Date Issued

  Tuesday, June 10, 1958
  66 years ago

• CPC

  • H04M3/40 - Applications of speech amplifiers
  • H04M19/04 - ringing-current generated at substation
  • H04Q1/4423 - using one signalling frequency

• US Classifications

  • 379 - Telephonic communications