METHOD FOR A COMMUNICATION SYSTEM, IN PARTICULAR FOR A TELEPHONE EXTENSION SUBSYSTEM IN WHICH INTERVENTIONS PERIODICALLY SWITCHES TO CHANGED TRAFFIC POSSIBILITIES.

摘要

In a telephone branch exchange system, the subscriber classes of service are centrally switched over for particular periods. For the subscriber terminals, a lower-value class of service is preset, for example, by the general switching-over to "exchange-barred". A telephone subscriber can break through the centrally controlled switch-over by dialling a particular code information (key code). This makes it possible to use the classes of service originally allocated to the relevant subscriber station at least for one call connection. Since this only takes place in dependence on the code information dialled, this provides additional security against misuse of subscriber stations, particularly those subscriber stations which are allocated higher-value classes of service. IMAGE