Also known as conference calling or audio conferencing, audio teleconferencing is the process of holding a meeting via telephone hookup. First developed during the middle of the 20th century as a business tool, this form of teleconferencing was once extremely expensive. Today, it is possible for individuals as well as organizations of all sizes to make use of telephone conference calls for very little expense.
Audio teleconferencing involves establishing a common point of termination for the phone signals of all parties that are to take part in a particular conference. This is accomplished with the use of a teleconference bridge, which receives inbound and outbound telephone signals from a local telephone switch. Depending on the structure of the conference call, either a passcode entered by the attendee will route the signal to the correct conference, or an operator will manually route the connection into the right conference session.
There are two basic types of conference calls. Operator dial-out services, also known as operator connected services, are the oldest type of audio teleconferencing. With this model, a conference call is booked in advance, reserving a certain number of lines and a specific duration. The customer provides the conference call service with the names and telephone numbers of all parties that are to attend the session. At the appointed time, a conference operator dials out to the attendees and places them into a common conference line. With this approach, the conference moderator is usually connected last. Many services offer the moderator the option of holding a roll call immediately after he or she is transferred into the teleconference session.
A second option is the dial-in conference. With this option, attendees dial a specific telephone number to connect with the conference bridge. An automated message urges the attendee to enter the passcode assigned to the teleconference. Once the correct passcode is entered, the attendee is automatically routed into the call.
There are several sub-categories of a dial-in conference. The most popular audio teleconferencing option today is usually described as a reservationless toll-free format. With this option, the moderator is assigned a permanent toll-free number, a permanent passcode or passcodes, and a maximum number of lines that can be used whenever the moderator likes. This option makes it unnecessary for the moderator to contact the teleconference service each time he or she wishes to conduct a meeting via conference call, since the credentials are active around the clock.
Many providers also still offer the option of a reserved toll-free dial in meeting. This audio teleconferencing option provides a toll-free number and passcodes on a one-time basis; there is no guarantee that the moderator will be able to use the same number and codes for future conferences. This format can also be used to set up what is known as standing or recurring conference calls, which take place the same day and time of day on a weekly, bi-weekly, or monthly basis.
A third sub-category of dial-in services is known as the toll-dial in call. This format works exactly like its toll-free counterparts. The difference is that instead of a toll-free number, all attendees dial into the teleconference bridge using a standard telephone number, complete with area code. Toll dial-in services saw a huge drop in usage during the 1990's, but began to resurface with the advent of cell phones and landline calling plans that made it possible for attendees to use a toll number and not incur long distance charges on their phone bills.
Over the years, service features have made audio teleconferencing increasingly user-friendly. Today, many services offer the moderator many tools to control the conference, including the ability to mute all other attendees, disconnect all lines at will, and make use of voice notifications when someone enters or exits the conference. Some of these features are available for additional charges, but many are considered part of the basic service, and are included in the flat rate per minute per line charge associated with the conference call service.