RCA ViSYS  4 lineAccessory Handset w/Call Waiting Caller ID Extended Range - up to 2000 feet with patented high powered digital tech. Handset Speakerphone-provides convenience of hands free communications. Handset to Handset communication-up to 16 handsets can be added to base system with individual directories and caller ID memories Call waiting caller ID-display shows name and number of new incoming call even if you're on the phone with another caller. Call forwarding/call tanser/call conference-allow advance call handling options Memory-speeds dialing of frequently used numbers. Intercom-allows convenient 2 way conversation between handsets or between handset and base without using the phone line. Advanced charging technology-provides maximum battery life