The Yealink T48S is a 16-line (with Firmware version V73) Gigabit SIP phone ideal for heavy phone use and traffic. The T48S has Yealink's Optima HD voice, supports Bluetooth headsets, and features a 7" color touch panel for swift, easy, and convenient switching between screens and applications. -3-way conferencing, One-touch speed dial, hotline, Call forward, call waiting, call transfer, Group listening, emergency call, Redial, call return, auto answer -7 features keys: message, headset, hold, mute, transfe