Wikipedia
IP-DECT is a technology used for on-site wireless communications. It uses the DECT air interface for reliable wireless voice and data communication between handsets and base stations and the well established VoIP technology for the corded voice communication between base stations and server functions.
The advantage is the circuit switched approach and therefore better specified quality of service for vocal communication than with Wireless LAN. IP-DECT offers do support lower rate data communication for the wireless part.
There are some of the traditional telephone equipment manufacturers and smaller enterprises that offer IP-DECT systems, both for residential (single base station/access points), as well as for enterprise usage (multiple base stations/access points) where it is important to cover large areas with a maintained speech path.
Reliable data on market success, sold quantities and market share are not publicly available (May 2009).