Samsung iDCS Full Duplex Speakerphone Module (Refurbished)Key Features: Used to upgrade an iDCS 18 Button Speakerphone or an iDCS 28 Button Speakerphone from half duplex to full duplex operation Allows the user to both transmit and receive at the same time providing a better quality speakerphone Ideal for the boardroom when multiple parties are on a call simultaneously Up to 3 external microphones can be added for even greater sound clarity in large rooms