Panasonic KX-TG2700S 2.4 GHz DSS Expandable Cordless Speakerphone with Caller ID 2.4 GHz frequency hopping digital spread spectrum technology Expandable to 8 handsets with optional Panasonic KX-TGA270S Digital duplex speakerphone; 4-way conferencing Handsets feature privacy mode, intercom/paging, and room monitor functions 6 selectable ring tones, 4 line backlit LCD on handsets