The History of VoIP
By Cloud Vision Technologies

This Article is a summary of more than 20 publications available to the public on the Internet.

first phone call

In December 1974 the first real-time conversation on the ARPAnet took place between Culler-Harrison Incorporated in Goleta, California, and MIT Lincoln Laboratory in Lexington, Massachusetts. This was the first successful application of real-time digital speech communication over a packet network and an early milestone in the explosion of real-time signal processing of speech, audio, images, and video that we all take for granted today. It could be considered as the first voice over Internet Protocol (VoIP), except that the Internet Protocol (IP) had not yet been established. In fact, the interest in real-time signal processing had an indirect, but major, impact on the development of IP. This is the story of the development of linear predictive coded (LPC) speech and how it came to be used in the first successful packet speech experiments. Several related stories are recounted as well.

In our modern times, voice-over-internet-protocol (VoIP) phone systems are commonplace. After all, they are highly affordable and have features beyond basic calling, such as SMS, video conferencing, and integrations with outside business software. However, VoIP popularity is relatively new in the broader scope of phone technology. Here, we’ll be looking at the major developments that have made today’s most well-known VoIP services possible. The following are the major milestones of the history of VoIP.

Linear Predictive Coding (1966)

Linear predictive coding (LPC) is a method used mostly in audio signal processing and speech processing for representing the spectral envelope of a digital signal of speech in compressed form, using the information of a linear predictive model. It is one of the most powerful speech analysis techniques, and one of the most useful methods for encoding good quality speech at a low bit rate and provides highly accurate estimates of speech parameters. LPC is the most widely used method in speech coding and speech synthesis.

Network Voice Protocol (1973)

NVP was first implemented in December 1973 by computer networking researcher Danny Cohen of the Information Sciences Institute (ISI), University of Southern California, with funding from ARPA’s Network Secure Communications (NSC) program. The major objective of ARPA’s Network Secure communications (NSC) project is to develop and demonstrate the feasibility of secure, high-quality, low-bandwidth, real-time, full-duplex (two-way) digital voice communications over packet-switched computer communications networks. This kind of communication is a very high priority military goal for all levels of command and control activities. ARPA’s NSC project will supply digitized speech which can be secured by existing encryption devices.  The major goal of this research is to demonstrate a digital high-quality, low-bandwidth, secure voice handling capability as part of the general military requirement for worldwide secure voice communication.

CELP Used for transmitting speech (1985)

CELP coders are linear predictive coders equipped with an ABS search procedure. They were invented in the 1980s by Bell Labs (under the supervision of B.S. Atal and M.R. Schroeder). Code-excited linear prediction (CELP) is the most widely deployed method for speech coding today, serving as the primary speech coding method in the adaptive multi-rate codec and in the more recent enhanced voice services (EVS) codec, both of which are used in cell phones and VoIP. At a high level, a CELP codec consists of a linear prediction model excited by an adaptive codebook and a fixed codebook.

Speak Freely. First VoIP Application (1991)

Speak Freely is a 100% software-based VoIP phone originally written in 1991 by John Walker, founder of Autodesk, and Brian C. Wiles. Over the years since, other VoIP applications popped up, but Speak Freely was the first VoIP application (or Internet telephone) released to the public. Brian had written another VoIP application in 1989 called RASCAL (short for Remote Audio Sound Card Application Link), and some parts of it were incorporated into Speak Freely.

First VoIP Application. Chat and Talk (1993)

VocalTec Communication released the first Chat and Talk application over internet to the public. VocalTec Communications Inc. is an Israeli telecom equipment provider. The company was founded in 1985 by Alon Cohen and Lior Haramaty, who patented the first Voice over IP audio transceiver. VocalTec has supplied major customers such as Deutsche Telekom, Telecom Italia, and many others.

The G.729 Speech Codec (1996)

G.729 is a royalty-free narrow-band vocoder-based audio data compression algorithm using a frame length of 10 milliseconds. It is officially described as Coding of speech at 8 kbit/s using code-excited linear prediction speech coding (CS-ACELP) and was introduced in 1996. The wide-band extension of G.729 is called G.729.1, which equals G.729 Annex J.

Because of its low bandwidth requirements, G.729 is mostly used in voice over Internet Protocol (VoIP) applications when bandwidth must be conserved. Standard G.729 operates at a bit rate of 8 kbit/s, but extensions provide rates of 6.4 kbit/s (Annex D, F, H, I, C+) and 11.8 kbit/s (Annex E, G, H, I, C+) for worse and better speech quality, respectively. G.729 has been extended with various features, commonly designated as G.729a and G.729b.

The Vonage Outburst (2001)

Vonage launched its VoIP offering for business users in 2001 under the name of (it changed its name to Vonage in December 2000). The firm was initially based in Melville, New York and was founded by CEO Jeffrey Citron, but in January 2001 Vonage moved to Edison, New Jersey. It then relocated its HQ again in 2005 to Holmdel, New Jersey (its current home).

Skype made it mainstream (2002)

Skype development in 2002 was financed by the Skype Group, founded by Swedish entrepreneur Niklas Zennström and the Dane Janus Friis, who had already an experience in venture IT business, founding in 2001 Kazaa Media Desktop (once capitalized as “KaZaA”, but now usually written “Kazaa”)—the famous peer-to-peer file sharing application. Skype calls to other users of the program and, in some countries, to free-of-charge numbers, are free, while calls to other land lines and mobile phones can be made for a fee ($2.95/month gets you unlimited calls in the USA).

The name Skype came from one of the initial names for the project—SKY PEer-to-peer, which was then abbreviated to Skyper. It appeared however, that some of the domain names associated with Skyper were already taken. Dropping the final r left the current title Skype, for which domain names were available.

Apple Launches FaceTime (2010)

Apple bought the “FaceTime” name from FaceTime Communications, which changed its name to Actiance in January 2011. On June 7, 2010, Apple CEO Steve Jobs announced FaceTime in conjunction with the iPhone 4 in a keynote speech at the 2010 Apple Worldwide Developers Conference. Support for the fourth generation iPod Touch (the first model of iPod Touch equipped with cameras) was announced in conjunction with the device’s release on September 8, 2010. FaceTime for Mac OS X was announced on October 20, 2010.

On March 2, 2011, FaceTime support was announced for the newly introduced iPad 2, which had forward- and rear-facing cameras.

On February 24, 2011, FaceTime left beta and was listed in the Mac App Store for US$0.99. Apple claims that it intended to provide the application free of charge, however, a provision of the Sarbanes–Oxley Act (2002) bars companies from providing an unadvertised new feature of an already-sold product without enduring “onerous accounting measures”.

WebRTC (2011)

WebRTC technology becomes widespread, which allows VoIP calls to be made in web browsers. WebRTC technology was first developed by Global IP Solutions (or GIPS), a company founded around 1999 in Sweden. In 2011 GIPS was acquired by Google and the W3C started to work on a standard for WebRTC. Since then Google and other major players in the web-browser market, such as Mozilla and Opera, have been showing great support for WebRTC.