Circuit arrangement for centrally controlled telecommunication exchanges, especially telephone exchanges, with two common control units operating in parallel and a replacement circuit in case of failure

摘要

Two parallel-operated control units each communicate via a respective discrete bus with a respective assigned group of switch devices, and given an alternate circuit based on one control unit simultaneously accepting the tasks for both groups, an alternate circuit bus is provided from the accepting control unit to the other group of switch devices and has bidirectional bus amplifiers connected therein, the one bus amplifier being supplied with voltage together with the accepting control unit and its group and the other bus amplifier being supplied with voltage together with the other control unit and its group. Given a voltage outage of the non-accepting control unit and its assigned group of switch devices, a signal is transmitted to the first-mentioned bus amplifier in order to provide the required disconnection of the alternate circuit bus by way of unequivocal electrical switch states and measures in that bus having supply voltage present.