Abstract: A cordless telephony system includes a switching exchange having a conventional switch which may be coupled to the public network. To avoid loading of such switch, the exchange also includes a backbone coupling network coupled to cluster controllers for respective clusters of base stations. Such network transports data between the cluster controllers during handover of a roaming mobile telephone set between different base stations. The system may be used as a private branch exchange operating with a central controller. The cluster controllers may be in the form of line cards which communicate with each other via the backbone coupling network, control being effected in a decentralized mode.