Optimal HD audio, full duplex technology Yealink Noise Proof Technology 20-foot (6-meter) and 360-degree microphone pickup range Two optional Wireless Expansion Microphones (CPW90) Built-in 3-microphone array 5-inch multi-touch screen with 720 x 1280 resolution 5-way conference call Built-in Wi-Fi (2.4GHz/5GHz, 802.11.b/g/n/ac) Built-in Bluetooth 4.0
