GDC-500H is a wireless handset that employs DECT technology to provide local in-building mobility. Wireless Radio Frequencies (RF) signals are exchanged between the handset and base stations (GDC-400B / 600B/GDC-600BE). Multiple base stations connect to the Wireless Management Interface (WMI) in your system. The WMI links the connected base stations forming a larger Base or Zone. Within this zone, transparent handover of active communications between base stations in the zone is supported.