Indications of which participant is providing information during a multi-party conference. Each participant has equipment to display information being transferred during the conference. A sourcing signaler residing in the participant equipment provides a signal that indicates the identity of its participant when this participant is providing information to the conference. The source indicators of the other participant equipment receive the signal and cause a UI to indicate that the participant identified by the received signal is providing information (e.g. the UI can causes the identifier to change appearance). An audio discriminator is used to distinguish between an acoustic signal that was generated by a person speaking from that generated in a band-limited manner. The audio discriminator analyzes the spectrum of detected audio signals and generates several parameters from the spectrum and from past determinations to determine the source of an audio signal on a frame-by-frame basis.