Milestone-Nomination:First Real-Time Speech Communication on Packet Networks


Docket Number: 2010-09

Proposal Link:

In the space below the line, please enter your proposed citation in English, with title and text. Text absolutely limited to 70 words; 60 is preferable for aesthetic reasons. NOTE: The IEEE History Committee shall have final determination on the wording of the citation

First Real-Time Speech Communication on Packet Networks, 1974 - 1982

In August 1974, the first real-time speech communication over a packet-switched network was demonstrated via ARPANET between MIT Lincoln Laboratory and USC Information Sciences Institute. By 1982, these technologies enabled Internet packet speech and conferencing linking terrestrial, packet radio, and satellite networks. This work in real-time network protocols and speech coding laid the foundation for voice-over-internet-protocol (VoIP) communications and related applications including Internet videoconferencing.


Clifford J. Weinstein and James W. Forgie, “Experience with speech communication in packet networks,” IEEE Journal on Selected Areas in Communications, Special Issue on Packet Switched Voice and Data Communications, Vol. 1, No. 6, December 1983.

Dan Cohen, “RFC0741: Specifications for the Network Voice Protocol,” 22 Nov 1977. Available at

Robert M. Gray, "The 1974 origins of VoIP," IEEE Signal Processing Magazine, Vol. 22, July 2005, pp. 87-90.

Robert M. Gray, Linear Predictive Coding and the Internet Protocol, NOW Publishers, 2010

N. Shacham, E. Craighill, A. Poggio, “Speech Transport in Packet-Radio Networks with Mobile Nodes,” IEEE Journal on Selected Areas in Communications, Special Issue on Packet Switched Voice and Data Communications, Vol. 1, No. 6, December 1983.

G. Falk, J. S. Groff, W. C. Milliken, M. Nodine, S. Blumenthal, W. Edmond, “Integration of Voice and Data in the Wideband Packet Satellite Network”

Packet Speech was featured both in a Special Issue of the IEEE Journal on Selected Areas in Communciations (1983) and in an IEEE Press Book (1990). Both included papers on the milestone accomplishments featured in this nomination.

IEEE Journal on Selected Areas in Communications, Special Issue on Packet Switched Voice and Data Communications, Vol. 1, No. 6, December 1983. (This special issue contains three of the papers above, as well as other papers on packet speech).

W. P. Lidinsky, D. Vlack (editors), Perspectives on Packetized on Packetized Voice and Data Communication, IEEE Press, Piscataway, NJ, USA 1990, ISBN:0879422637 (This 1990 IEEE Press also contains three of the papers above, as well as a number of other papers on packet speech and data).

Please also include references and full citations, and include supporting material in an electronic format (GIF, JPEG, PNG, PDF, DOC) which can be made available on the IEEE History Center’s Web site to historians, scholars, students, and interested members of the public. All supporting materials must be in English, or if not in English, accompanied by an English translation. If you are including images or photographs as part of the supporting material, it is necessary that you list the copyright owner.

In the space below the line, please describe the historic significance of this work: its importance to the evolution of electrical and computer engineering and science and its importance to regional/national/international development.

This pioneering work on speech in packet networks developed and demonstrated systems which were forerunners of the voice-over internet protocol (VoIP) systems that are now so widely in use. The real-time voice work included development of a new Network Voice Protocol (NVP), because the packet and reliability constraints of the available Transmission Control Protocol (TCP) implementation made it unsuitable for real-time communication. This protocol development was an immediate forerunner of the separation of TCP and IP, so that the real-time packet speech work played a large role in the development of the protocols, which are still in wide use today. The technology and protocols for real-time speech over packet networks also enabled other real-time internet applications such as packet video, so that now systems like Skype enable real-time voice and video at home and in offices for extremely large number of people.

What features or characteristics set this work apart from similar achievements?

This work combined major developments in multiple areas, including the first real-time implementations of narrowband LPC speech coding on digital signal processors, network protocols to enable real-time packet delivery, strategies for reconstituting speech, techniques for reconstitution of speech from packets arriving at non-uniform intervals, packet speech conferencing techniques, and interoperation over different types of packet networks (landline, Ethernet, satellite, radio). Another feature was the outstanding collaboration among organizations and across technology areas. Finally, the long-term impact is a major feature which sets this work apart, as evidenced by the wide use of VoIP and related application such as packet video.

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