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-4860DX_B/54 Delegate Unit, the HCS-4860CX_B/54 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. The chairman unit can also be used to apply/cancel a request-to-speak and turn off all active microphones.