Us Robotics Speakerphone Conference Link Cs1000 SimulCom's full duplex technology, with acoustic sound cancellation, enables clear, interactive discussions. Automatic Gain Control allows you to move freely about the room while maintaining reliable sound quality reception. Three built-in microphones deliver 360 degree coverage. Keypad works just like a standard telephone with mute, redial and flash keys. Easy Setup with no dip switches or user tuning required