AT&T 3 Handset Cordless Phone with Answering System with Caller ID/Call Waiting DECT 6.0 Digital technology Full Duplex Handset Speakerphone Expandable up to 5 handsets (uses EL50005 accessory handset) Caller ID/call waiting, 30 name and number caller ID history Digital answering system, 22 minutes of digital recording time ECO mode power-conserving technology, 50 name and number phonebook directory Volume control