AT&T E250 Accessory Cordless Handset, Silver | Requires an AT&T E2500 Series Expandable Phone System to Operate 2.4 GHz frequency-hopping digital spread spectrum signal For use with AT&T E2525 and E2555 expandable phone systems Answering machine access from handset; 50-number phone directory Caller ID/call waiting, 50-call memory; headset compatible Intercom, conferencing, and call waiting