Motorola MD751 5.8 GHz Digital Expandable Cordless Phone with Caller ID (Black/Silver) 5.8 GHz digital signal; expandable to 8 handsets, 1 included Visual call-waiting and voicemail-waiting indicator Caller ID with 50 memory locations; shared phone book memory Hands-free intercom, handset-to-handset intercom, room monitoring Speakerphone, 3-way conferencing, custom ring tones