What is an Audio Bridge?

Malcolm Tatum
Malcolm Tatum

Also known as an audio teleconference bridge, an audio bridge is a piece of equipment that is used to create telephone conference calls. An audio bridge serves as the point of termination for the connections that are to take place in the collective call, creating a common hub where all the lines can connect and interact with ease. The audio bridge is the oldest type of teleconferencing bridge, and is still in regular use in many parts of the world.

A teleconference bridge can be used to facilitate conference calls.
A teleconference bridge can be used to facilitate conference calls.

The audio bridge has been in production since the middle of the 20th century. The earliest designs were large and rather cumbersome pieces of equipment that were extremely expensive. Typically, only telephone service providers owned audio bridges, although by the late 1960’s, some larger corporations with their own internal communications systems were using audio bridge equipment to conduct conference calls between company facilities that were part of the internal network.

With the deregulation of the telephone industry in the United States in 1984, a number of independent conference call providers went into business. Some designed their own proprietary audio bridges, and established contracts with local and long distance carriers to supply the line capacity necessary to provide conference call services to their clientele. Much smaller than the bridges of the 1950’s, these newer bridges had a larger line capacity, and were much easier to manage in terms of dialing out to and connecting conference attendees.

With the advent of the 1990’s, the audio bridge began to undergo additional changes. Many bridge manufacturers abandoned the older analog technology in favor of newer digital configurations, a move that made it possible to increase line capacity on the bridges, as well as provide a more sensitive level of sound quality on the calls. Along with upgrades in capacity and sound, the newer audio bridge designs also made it possible for attendees to dial into the bridge facility, rather than requiring an operator to dial out to each individual slated to attend a conference call. This new approach, popularly known as dial-in or meet-me conferencing, was made even easier with the creation of unique passcodes that could be used to route each caller to the correct conference call. Within a couple of years, dial-in conferencing, especially services using toll-free numbers for bridge access, were much more popular than the older dial-out approach.

Internet communications also led to changes for the audio bridge. The ability to stream a phone signal across the Internet led to the ability of international locations to participate on domestic conference calls for a fraction of the costs of only a few years before. This led to the creation of Voice over Internet Protocol, or VoIP, audio bridges that rely on the placement of equipment at phone switches to convert the online audio streams into standard digital phone signals at each end of the connection. The end result has been the continual decrease in the cost of audio conferencing, making this service available to businesses of all sizes, as well as individuals.

Today, the audio bridge is sometimes overlaid with video capability. This hybrid bridge uses the same circuits to carry both voice and video, rather than requiring two separate facilities to manage the meeting. While more expensive than the traditional audio-only bridge, the audio video bridge has increased in popularity in recent years, especially among corporations with an international presence.

Malcolm Tatum
Malcolm Tatum

After many years in the teleconferencing industry, Michael decided to embrace his passion for trivia, research, and writing by becoming a full-time freelance writer. Since then, he has contributed articles to a variety of print and online publications, including EasyTechJunkie, and his work has also appeared in poetry collections, devotional anthologies, and several newspapers. Malcolm’s other interests include collecting vinyl records, minor league baseball, and cycling.

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Discussion Comments


@Vincenzo -- I can't agree with that. All that has happened is the audio bridge has adapted to embrace new technology such as digital phone lines and video conferencing. That's kind of what happens when it comes to technology. People will improve something that already exists before creating something completely new. That adaptation is what has happened with audio bridges.


I don't know how accurate it is to say that the audio bridge is the oldest piece of telecommunications equipment on the planet and is still in use. The true is, the audio bridges used these days are in no ways similar to the ones used before digital phone lines came into being.

They are so different, in fact, that perhaps we should call them something other than audio bridges. We are dealing with new equipment here, so perhaps a new technical term for those things is appropriate.

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