Abstract: A private branch exchange (PABX) with an integrated mobile part for controlling cordless terminals (HS) is established, which can be operated from base stations (BS).The private branch exchange (PABX) contains freely configurable interface modules (I/F) for wired (DE) and cordless (HS) terminals, which can be operated from a base station (BS). A central control unit (PABX-CPU) is provided to control all call handling and service feature control tasks, and a subordinate control unit (Mobile-CPU) for call setup and switch-off control of the cordless terminals (HS) in accordance with a set of assigned call numbers. The control units (PABX-CPU, Mobile-CPU) and the interface modules (I/F) are connected with each other through a bus system (BUS).

Abstract: An installation is described for establishing a connection between private branch exchanges (PABX), each of which has a base station allocated within a determined geographic area (GA), where the base station provides a determined number of utilization channels served by telecommunication, through which mobile cordless terminals communicate with the base station, and thereby with the branch exchange, throughout the geographic area. The base station (BS.sub.2) of a second branch exchange (PABX.sub.2) is located within the geographic area (GA) of a base station (BS.sub.1) of a first branch exchange (PABX.sub.1), and a wireless cross linkage is established by the two base stations (BS.sub.1, BS.sub.2) and their telecommunication (PABX.sub.1, PABX.sub.2).