A computer system for transmitting two or more types of signals. Each type of signal is assigned a priority level. Signals of a particular type are transmitted as they become ready for transmission, unless signals of a different type having a greater priority become ready for transmission. In that case, the transmission of the low-priority signals is interrupted to allow transmission of the high-priority signals. The transmission of the low-priority signals is resumed after the transmission of the high-priority signals is complete. In a preferred embodiment directed to conferencing systems, audio signals are assigned higher priorities than video, data, and control signals in order to provide a high-quality to the audio portion of a conferencing session.