CENTRALLY CONTROLLED DIGITAL TIME DIVISION MULTIPLEX TELEPHONE EXCHANGE

The line trunk groups (LTG) for subscriber and junction lines (VL) are allocated to one another in pairs in such a manner that when central sections (GS, GP) of one group of a pair fail, the central sections of the other group can also be utilised for handling the telephone traffic which relates to the lines (VL) connected to the group affected by the failure. Due to a corresponding extension of the group storage (GS) and increase in the speed of access to these stores, facilities (SU) which are connection-individually effective and form a decentralised component of the groups are still usable by connection via the group storage of the other group when the central sections of a group fail.