IP Telephony Intellectual Property

This page provides information on patents that have been reported to Packetizer that potentially cover packet-switch conversational protocols, including Voice over IP (VoIP) and videoconferencing. There are links to pages that reportedly provide information that might demonstrate some prior art to patent claims. If you would like to see something listed here or have comments to make, please send e-mail to the webmaster.

United States

• Lucent
  • 4,100,377 - Packet transmission of speech (1977)
  • 4,748,620 - Time stamp and packet virtual sequence numbering for reconstructing information signals from packets (1986)
• Henley, et al.
  • 5,526,353 - System and method for communication of audio data over a packet-based network (1994)
• MultiTech
  • 5,452,289 - Computer-based multifunction personal communications system (1993)
• BTG (acquired from Intelligence at Large)
  • 5,623,490 - Method and apparatus for multiple media digital communication system (1996)
  • 5,995,491 - Method and apparatus for multiple media digital communication system (1997)
  • 6,104,706 - Method and apparatus for multiple media digital communication system (1999)
• VoIP, Inc.
  • 6,501,837 - Telephone call connection architecture

Potential Source of Prior Art

• How the Internet Came to Be - Vinton Cerf
• Speak Freely Development Log - John Walker
• RFC 741: Network Voice Protocol - Danny Cohen
• RTP History - Henning Schulzrinne
• Network Bibliography - Henning Schulzrinne (Search for "packet voice")
• Voice communication across the Internet: A network voice terminal - Henning Schulzrinne, July 1992