AT&T TL90073 Accessory Cordless Handset, Silver/Black | Requires an AT&T TL92273, TL96273, or Other Models to Operate Accessory Handset Only. Requires a TL92273 or TL 96273 to Operate Make and Receive Landline and Cellular Calls Store 6000 Directories from up to 4 Different Cell Phones Mobile Notifications Virtual Multi-Line Operation Caller ID Announce DSL Subscribers may need to us a DSL Filter For optimal performance batteries should be charged for 16 hours prior to use