Abstract: If a failiure of a switching exchange occurs caused by an error, a large number of subscribers are involved. Therefore, switching exchanges are to be protected against a failure. Thereto, in the switching exchange described hereinbefore, the switching network is constituted by three parallel sub-switching networks, whereas each sub-switching network performs the integral switching operations. A selection logic selects for each connection from the data that have been switched three times always the data which have the highest probability of being error-free.