Maintenance principles for automatic telephone exchange plant

The maintenance of the complex mass of equipment which constitutes the modern automatic telephone exchange requires to be different from that of most engineering plant, mainly because the finding of the faults is so much more difficult than their subsequent repair. A comparison of maintenance practices throughout the world needs first to be qualified by differences in the design of systems and plant. With this reservation, the experiences in the British Post Office and abroad with overhauls, cleaning, routine testing, alarms and monitoring devices are then reviewed and compared. This leads to the compilation of a pattern of maintenance effort in relation to the effect on service and reveals the many alternative methods of prevention, disclosure and correction of service failures. The relative efficiency of methods of reducing the number of plant faults or reducing the number of calls affected by each plant fault is then discussed, and it is suggested that there may be a drift from the old-established policy of routine preventive maintenance in favour of a flexible and qualitative policy to suit the local condition of the plant. At the same time, the design of maintenance aids appropriate to modern technical developments in switching systems is reviewed. The paper concludes with a Bibliography and a list of definitions of terms that are used with a restricted meaning in the text.