DEVICE TO CONTROL THE CORRECT FUNCTIONING OF A PAIR OF PROCES- SERS ACTING ONE AS READY RESERVE FOR THE OTHER

摘要

An apparatus DC is provided for detecting malfunctioning of a pair of duplicated processors arranged to control systems for which an especially high degree of reliability is required, such as telephone exchanges. The programme for the two processors comprises control messages which are sent on respective input-output channels in accordance with predetermined modes of operation. The apparatus is designed to detect incorrect operation of the two processors by examining the messages generated by them. More particularly, failure to generate such messages, incorrect sequences of such messages, or sending of non- programmed messages by one processor results in it being excluded from the control process, which is then committed to the other processor.