Yealink W73H High-performance IP DECT Handset, HD Audio, Long Standby Time 400 hours, Up to 35 hours talk time, Noise Reduction,

An Internet Protocol (IP) phone, also known as a VoIP phone (Voice over IP) uses technologies for placing and transmitting telephone calls over an IP network, such as the Internet, instead of the traditional public switched telephone network (PSTN).