Conference Bridge

What Is A Conference Bridge?

A conference bridge allows a group of people to participate in phone call.  The most common form of bridge allows participants dial into a virtual meeting room from their own phone.  Meeting rooms can hold dozens or even hundreds of participants.  This is in contrast to three-way calling, a standard feature of most phone systems which only allows a total of three participants.  For most phone systems, conference bridging is an add-on feature that costs thousands of dollars.

Key Features

Conferencing systems typically support multiple conference rooms, each of which can contain multiple participants.  The total number of rooms and participants varies depending on the model, hardware capabilities and licensing terms.

Most conference bridge systems allow the administrator to assign DID numbers to conference rooms.  In some cases as single DID number connects callers with an IVR application that prompts for a room number.

Conference rooms can optionally be secured by a PIN number.  Some systems use a common PIN for all participants while others use custom PINs for each.

Advanced conferencing systems include a graphical user interface that allows all participants to see who is currently speaking and optionally who has joined the conference.  Admnistrators and moderators generally have a more comprehensive view that includes advanced controls.

Some conference bridge systems include dynamic meeting rooms: rooms that are created on a scheduled basis.  This is particularly common for larger systems where capacity planning is an issue.

Key Benefits

Conferencing allows companies to save significantly on travel costs.  In-person meetings are costly and time consuming.  A conference bridge system can pay for itself in just one avoided "on-site" meeting.

Conferencing is the core of collaboration and enables distributed or virtual teams.  Combined with VoIP connectivity for remote workers, conferencing makes it simple and affordable for a team to function across a diverse geography. 

Asterisk As A Conference Bridge

Asterisk includes a standard application called ConfBridge.  ConfBridge is a high definition-capable conference bridge component that makes it easy to build stand-alone conferencing services or to integrate conferencing into other solutions, including IP PBX systems.

Creating a conference room is trivial, requiring only a few lines of Dialplan script. ConfBridge includes a wealth of administrative features (mute participants, add / remove callers, etc.) and a rich event structure that allows developers to build fully integrated user interfaces.  ConfBridge also supports basic video conferencing, though this feature is currenly considered experimental.

For information on Asterisk-based conference bridges, see the AsteriskExchange.