Voice Conferencing

If you are looking for a tool for voice conferencing try BigBlueButton which enables universities and colleges to deliver a high quality learning experience to remote students. The Web Participants window lets you see all the users logged into the current session. Any user can raise their hand to get the attention of the presenter.The Voice window shows all the users that are currently connected to the voice conference bridge, either by calling in directly or using the built-in voice over IP client. You can also eject participants from the voice conference by clicking on their name and then clicking the eject button. 

There are three user roles in BigBlueButton: viewer, presenter, and moderator. The viewer who are the students have no authority within the conference; their primary role is to view the presentation as well as chat amongst other participants. The presenter has all the same capabilities as a participant, with the added features of uploading slide presentations, and sharing their desktop. The presenter can share their video by clicking the Start Camera icon. The moderator has all the capabilities as a participant, with the added features of uploading presentations and sharing their desktop.