the invention relates to a network , in particular a pa profibus network having redundant properties and a linear topology . two line ends are connected to a redundancy manager which disconnects said line ends in error - free conditions and connects them in error conditions . said redundancy manager supplies voltage to the first line end for operating customers &# 39 ; mobile telephones each of which is connected to the network by a branching unit . after receiving a supply voltage on one connection thereof , said branching units check the state of a cable which is connected to the other network connection and transmit the supply voltage in the faultless condition thereof only . when the redundancy manager does not detect the supply voltage on the other end of the line end at least during a predetermined space of time after voltage supply , said redundancy manager supplies the voltage thereto . a cable having a disturbance is then disconnected from the line by the adjacent branching units .