Signalling Systems for international telephony; A historical and technical review

History of signalling in international telephony is traced by a study of published literature. It was found that many of the principles and philosophies which are nowadays considered to be modern and new, originate from the period 1920-1935. There were surprisingly few literature references found in the studied literature, indicating that literature study was not an expedient in developing signalling systems. This is probably the reason that some of the basic ideas of signalling were sometimes lost, and had to be rediscovered by telephone engineers several years later. It can be found also that a clashing of philosophies and a lack of co-operation can trouble and delay development, but that ultimately the subscriber's wish for quick, reliable and cheap service will indicate the direction in which progress can be made.Applied SciencesElectrotechniekAutomatische Verkeerssysteme