The stylish and ergonomically designed chairman unit has all the necessary facilities to enable the user to chair a conference. It has excellent immunity to RF interference from mobile phones. Similar in appearance to HCS-4891DVS/50 Delegate Unit, the HCS-4891CVS/50 Chairman Unit includes a microphone priority button. When pressed, the priority button causes all currently active delegate microphones to be switched off temporarily or permanently, allowing the chairman to take control of the meeting. A 4.3" touch screen can display speaking list, sign-in and voting information, channel number and language name, conference service, operation menu, etc. Channel selection is automatically limited to the number of language channels available.