A wireless intranet office (WIO) concept is disclosed, which integrates an
IP based Intranet environment (27) and GSM network providing mobile
telephones (21) with access to GSM through the GSM network or via the
intranet. Access through the intranet to the GSM MSC (26) is provided by
a WIO interworking unit (24) which may comprise several network entities
(e.g. intranet mobile cluster (241), intranet location register (242),
WIO gatekeeper (243), WIO gateway (244) and H.323 gateway). A dual mode
terminal for such a system is also disclosed.