Abstract: A process for integrating cordless telephone networks into cellular mobile phone networks by using dual-system terminals which support communication over both a cordless telephone network and a mobile phone network. In the process, the mobile phone network assigns each cordless telephone network usable by a specific subscriber an own Location Area, to which a subscriber specific call number is allocated. A continuous check is made whether the subscriber is in the Location Area of the cordless telephone network available to him, and if so, then any call incoming via the mobile phone network is completed optionally or automatically by a mobile phone switching center using the call number assigned to the Location Area.