In the past few years, corporations have gotten bigger and more spread out. Many American employees -- more than 44 million in 2004 -- also do at least some of their work from home [ref]. Since offices and employees can be thousands of miles apart, getting everyone into the same room for meetings and training has become decidedly impractical for a lot of companies.

That's why teleconferencing -- the real-time exchange of information between people who are not in the same physical space -- has become such a big industry. The American audio conferencing industry alone reported $2.25 billion in revenue in 2004 [ref]. Through teleconferencing, companies can conduct meetings, customer briefs, training, demonstrations and workshops by phone or online instead of in person.

In this article, we'll look at different types of teleconferencing, from conference calls to online meetings.

The simplest phone teleconference is a three-way call, available in many homes as a service from the telephone company. Another very simple (but not necessarily effective) method is to have two groups of people talk to one another via speakerphone. The limits of three-way calling and the sound quality of speakerphones make both of these options impractical for most businesses.

Conference calls let groups of people -- from a few to hundreds -- communicate by phone. Banks and brokerages often use conference calls to give status reports to large numbers of listeners. Other businesses use conference calls to help coworkers communicate, plan and brainstorm. To connect to the call, attendees call a designated number (MeetMe conferencing), or an operator or moderator calls each participant (ad hoc conferencing).

Conference calls connect people through a conference bridge, which is essentially a server that acts like a telephone and can answer multiple calls simultaneously. Software plays a large role in the bridge's capabilities beyond simply connecting multiple callers.

A company can have its own bridge or can contract with a service provider for conference call hosting. Providers frequently offer add-on features for conference calls, such as:

  • Attendee polling
  • Call recording ­
  • In-call operators or attendants

Companies using Voice over IP (VoIP) telephones can also host conference calls themselves if the VoIP software supports them.

Many phone conferencing systems require a login and personal identification number (PIN) to access the system. This helps protect confidential and proprietary information during the call.

Video phones can add a visual element to conference calls, but businesses often need to share other visual information.