ATT Dect 6.0 Four Handset Bluetooth Answering System with Caller Id/call Waiting TL92420 Expandable up to 12 headsets. BLUETOOTH - Simultaneously Connect up to 2 Bluetooth phones (or 4 bluetooth enabled devices). Make and receive phone calls from 2 bluetooth connected phones (including 3 way conference call). Download the phone book from your cell phone. Wall mountable Answering System with Caller ID/Call Waiting DECT 6.0 Digital Energy Star rated. T-Coil hearing aide compatiable/