The integrated systems have certain advantages, which unfortunately, however,only be<strong>com</strong>e noticeable if fairly large portions <strong>of</strong> a telephone networkoperate on this basis. The advantages derive from <strong>the</strong> fact that <strong>the</strong> sameinformation carriers are used throughout <strong>the</strong> system. The conventionalswitching technique with space separation may be said to be integrated withordinary physical circuits; if from <strong>the</strong>re we proceed to multichannel systems,<strong>the</strong> exchanges as well should be electronic; and for <strong>the</strong> whole <strong>com</strong>municationsystem to be integrated, <strong>the</strong> same information carriers should be used throughout,which in practice would involve pulse systems.Within paren<strong>the</strong>ses it may be remarked that integrated systems on afrequency separation basis would require electronic exchanges on <strong>the</strong> samebasis. This is not practicably possible without easily switchable filters, <strong>of</strong>which at present <strong>the</strong>re seems to be no prospect.Advances in System Engineering and AnalysisThe enormous advances in <strong>the</strong> field <strong>of</strong> ma<strong>the</strong>matics during <strong>the</strong> last decadeswill bear fruit also in telephony. Ma<strong>the</strong>matical statistics in particular will findprogressive applications. First <strong>the</strong>re is traffic research, a classic field forma<strong>the</strong>matical statistics. With <strong>the</strong> breadth that this research now has in <strong>the</strong>world, many a long-debated problem may well find its solution. The nature<strong>of</strong> telephone traffic will undoubtedly be fur<strong>the</strong>r elucidated. Some practicalproblems which will be cleared up are minimization <strong>of</strong> <strong>the</strong> number <strong>of</strong> switchingpoints in switching networks, and queuing problems with different types <strong>of</strong>interworking markers. Catalogues will be issued <strong>of</strong> gradings and so on. Digital<strong>com</strong>puters will be used to a greater extent for different problems <strong>of</strong> telephonetraffic analysis.A related sphere <strong>of</strong> applied ma<strong>the</strong>matics, operations analysis, will also havewide applications. Certain fundamental problems are likely to be dealt with.One such problem, with wide implications, is <strong>the</strong> analysis <strong>of</strong> whole telephoneplants in order to obtain uniform dimensioning in every respect, as regardscongestion, attenuation and fault rate. The <strong>com</strong>mon denominator, so to speak,will be <strong>the</strong> inconvenience or cost to <strong>the</strong> subscriber or nation resulting from<strong>the</strong>se inevitable imperfections. Different types <strong>of</strong> fault will be evaluated.Digital <strong>com</strong>puters provide an entirely new means <strong>of</strong> analysis <strong>of</strong> alternativesolutions for <strong>the</strong> planning and location <strong>of</strong> exchanges. Maintenance, faulttracing etc. will be dealt with by operations analysis.It was thought that <strong>the</strong> rediscovery <strong>of</strong> Boole's algebra in <strong>the</strong> forties wouldprovide a short-cut in <strong>the</strong> design <strong>of</strong> relay circuits. This hope was disappointedsince <strong>the</strong> setting <strong>of</strong> <strong>the</strong> problem is as difficult as <strong>the</strong> finding <strong>of</strong> <strong>the</strong> solution.Boole's algebra, moreover, does not appear to be sufficiently flexible whenrelay times as well enter into <strong>the</strong> problem. Ano<strong>the</strong>r approach will probably betried, by programming a digital <strong>com</strong>puter to solve <strong>the</strong> problems. This wouldundoubtedly be no easy task and would take a considerable time to develop.It would be easier to check a found solution in a digital <strong>com</strong>puter. Forproblems <strong>of</strong> this kind <strong>the</strong> <strong>com</strong>puter technique with programmed logic hascertainly had a great influence on <strong>the</strong> design <strong>of</strong> markers and similar equipment.Digital <strong>com</strong>puters have for a long time been used in an entirely differentfield, for <strong>the</strong> <strong>com</strong>putation <strong>of</strong> filters. Even very <strong>com</strong>plicated filters can now
e calculated at a reasonable cost. One problem which has hardly been possibleto attack earlier, for filters with many <strong>com</strong>ponents, is to calculate <strong>the</strong>tolerances that can be accepted consistent with <strong>the</strong> requirements on <strong>the</strong> filter.This is manifestly <strong>of</strong> great economic importance. Clearly we are at <strong>the</strong> initialstage <strong>of</strong> a development which will give us better and cheaper products for alower engineering effort.The analog <strong>com</strong>puters also have <strong>the</strong>ir given sphere <strong>of</strong> use: <strong>the</strong> preparationand dimensioning <strong>of</strong> analog systems such as amplifiers and servo systems, e.g.for pilots in carrier systems.These are some gleanings <strong>of</strong> what we may look to in telephony during <strong>the</strong>near future. They represent an extrapolation <strong>of</strong> <strong>the</strong> existing situation, with apersonal colouring which can undoubtedly be contradicted on many points.In one respect we can be quite certain that <strong>the</strong> future will differ from ourprophecies today. New inventions, at present unknown or still in <strong>the</strong>ir birththroes,will give a richer spectrum to telephone engineering. Warrant <strong>of</strong> thisis <strong>the</strong> growing cadre <strong>of</strong> able technicians working in telephony throughout <strong>the</strong>world, as also <strong>the</strong> growing market for telephone service which is a source <strong>of</strong>satisfaction for administrations and for industry alike.113