TL-3300 digital conference system allows the delegate to speak, request to speak and listen to the speech. Each discussion unit comes with headphone jack and volume control for the delegate to listen to the floor audio, and adjust volume level for comfortable listening. 1 to 4 delegate microphones can be active at the same time. Highly resistant to mobile phone interference. Supports SD/HD video camera tracking. Multiple chairman /vice-chairman units are allowed. Pluggable gooseneck microphone. Easily hidden unit connecting cables.