Method for increasing the operational reliability of bus systems used for transmitting information in communication switching systems

摘要

In a bus system consisting of data and control lines, to which a number of access stations with their own control devices are connected in parallel, an automatic detection of faulty lines and automatic switching to stand-by is to be made possible. A test signal is sent out at predetermined time intervals whilst, at the same time, a special test word is sent on the data and control lines to be checked which are intended for the information exchange. The inverted bit pattern of this test word is transmitted with the next test signal. In the access stations, memories are provided for receiving these test words, the content of which is compared bit by bit. A line is detected to be faulty if the associated bits are identical in both memories. Switch-over to an in each case predetermined stand-by line is then effected with the aid of a switching device. This method makes it possible for operation to be maintained even when a defect occurs on a line belonging to the bus system. The operation can be maintained until the stand-by lines are used up. It is only then that a repair is absolutely necessary.