In switching network units which operate employing an information memory featuring cyclic input and random reading, the number of connections is particularly limited by the fact that during random reading it is not possible to exceed a specific speed. They are normally designed in such a manner that, to a full extent, they can effect both time-wise switching and spatial switching. In these units, the speed restriction during random reading means that the number of connections normally cannot exceed a certain value. Moreover, the facility of time channel conversion to a full extent in units of central switching stages represents an unnecessary expense. Such units are therefore constructed from a plurality of identical modules whose equivalent inputs are connected to one another and into which, during each pulse frame, more PCM words are input than PCM words are stored therein or can be read in random therefrom. Therefore, the time shifts which can be achieved serve primarily for purposes of spatial assignment, although the expense in comparison to the full time-spatial switching units is lower and a larger number of incoming lines can be connected without exceeding the permissible reading speeds.