Communication system

The invention relates to a communication system with subscriber terminals (10, 11, 12) which can be coupled to one another via at least one switching device (1, 2) and to each of which a plurality of telephone numbers, for which associated telecommunications parameters can be defined, can be assigned. It is proposed to provide storage of the telecommunication parameters in storage means (HUS, VUS) of the subscriber terminals (10, 11, 12). In a change of assignment of a subscriber number (PN1) from a first subscriber terminal (12) to a second subscriber terminal (11), a transmission of this subscriber number (PN1) belonging telecommunications parameters to the second subscriber terminal (11) is triggered. The invention is preferably used in ISDN switching systems with ISDN telephones as terminals.