Motorola SD4551 Digital Cordless&nbsp;System Phone, SD4500 Series Add up to 8 cordless devices per base, with no additional phone jack required Does not interfere with wireless home networking devices Caller ID with visual call waiting lets you see incoming caller's name and number before you answer Long battery life (up to approximately 6 hours talk time, approximately 6 days standby time) 15 different melody ring tones can be personalized to identify incoming callers