From the Manufacturer The ultimate two-line phone system for the home or office, this 2.4 GHz digital spread spectrum system features a digital answering system with a separate mailbox for each line. It includes handset and base speakerphones, caller ID/call waiting compatibility (with paid local service), a 50-number phone book directory (in both base and handset), and headset compatibility. Expand your VT 20-2481 by adding up to seven accessory handsets (model VT 20-2420) without additional phone jacks. Bring telephone service to rooms where it was previously unavailable. Product Description -Expandable up to 8 handsets -Dual display alphanumeric call waiting caller ID -Dual keypad with full duplex base speakerphone, handset speakerphone -4-line display; 2.5mm headset compatible -UPC 735078001382