’PHONES

New Zealand Times, Volume XXXVII, Issue 8360, 21 February 1913, Page 11

’PHONES

THE AUTOMATIC SYSTEM. EXPERT'S RECOMMENDATION. MELBOURNE, February 13. Mr J. Hcaketii, chief electrical engineer in the Postmaster-General's Department, to-day furnished the Minister with a report of his recent investigations in England, tho Continent, and America, into tho working of the automatic telephone system. He stated that in the seven and a_ half years which have elapsed since his previous investigation many advances have been made in automatic telephony so far as tho Strowgcr system is concerned, “These changes,” says Mr Hesksth, “have made it possible to say that from an engineering point of view this system, which is one that has attained the widest acceptance in actual practice, will now meet in a satisfactory manner all the various requirements of a local telephone system. Whether any automatic system will perform all the required functiana at the some or at a lower cost than the manual system, or whether there are reasons apart from the cost and engineering considerations to which weight should be given in any decision, must be determined by the circumstances of each case. Chief among the factors in this comparison is the question of annual cost. These should include interest depreciation, including obsolescence, maintenance, sinking fund, operating cost, insurance or taxes, and administrative charges. The information gained on the tour will etnbalo- me when the necessity arises to compare tho different schemes on the basis of annual costs within a reasonable margin of certainty. In exchanges, with over a certain number of lines connected, the cost of mechanical switching is less than the cost of manual switching. After taking all the factors into consideration, the use of mechanical switching will be justified in exchanges haring over 500 lines connected, and the . advantage in cost and also in-other directions will increase with the number of exchanges in network. THE COST. "Th© first cost of an automatic exchange equipment is from two to three times tho cost of manual equipment, hut there would be a decrease in the cost of operating which would counterbalance this increased first cost. In additien to the advantages of automatic switching mechanism as such, it is also possible that in certain cases economy in line construction may result from the adoption of an automatic or (end-automatic system. The question of staff has a very important bearing in arriving at any decision as to adopting an automatic switching mechanism. At the present rate of , growth there will be five times tho number of telephones, and therefore at least five times the staff, within fifteen years. 'This growth will affect not only the cost of the service, but aa the staff increases, so in a young community will jtha difficulty in obtaining ade-quately-trained officers. These comaidcratiouf inevitably react upon a manu-ally-operated service, and must bo given duo weight in considering the adoption of automatic mechanism. LINE WORK. ‘‘One of the first essentials towards a change from a manual to aa_ automatic system is the reconstruction of all defective lino work, and the mtrodUotioq, of metallic circuits for every subscriber, with the consequent advantage of freedom from hearing other Qsers or being overheard by them. In +.hlfa connection it is desirable ,to . empffijgjgn the fact that tho complaints ogjfinst a manually-operated, system are not levelled against the average service, fir very few of the subscribers would complain of having to watt an average of ten, twelve, or even fifteen seconds if it is against tho exceptional delay of from thirty seconds upwards that is tho average of the manual system. On the other hand, tbe_ time required to make each connection is approximately the same, and during the whole of this time the caller Is hlmanif busily occupied completing the connection, so that be does not notice Hie lapse of time, but in any case it is so short that it Kills for no adverse comment. FREEDOM FROM INTERRUPTIONS “ There is no question but that with a. -well-designed automatic mechanism the certainty of establishing a desired connection, and the freedom from interruptions during conversations, can bo made at least as satisfactory as in the best manual systems. My strong opinion is that the system to which we must look in the future, at least so far as Australia is concerned, is the full automatic and the semi-aqtomatio. Whilq 1 am satisfied, however, that the full automatic system is tho inevitable conclusion so far as the larger networks in Australia are concerned, it may bo necessary to advance to this position by two steps instead of by one. The economy of a semi or full automatic system is more pronounced in a network having two or more exchanges, for the reason that to operate such exchanges manually two groups of operators are needed for the local traffic, via., tiie ‘ A,’ or subscribers’ operators, and tho ‘ B ’ or incoming junction lino operators. In the semi-automatic system, when applied to a complete -network, tho number of ‘ A ’ operators is reduced by from 50 to 75 per -cent— and the ‘ B ’ operators are eliminated entirely. In -too full automatic system tho whole of tho operators roquired for tho local traffic are, of course, eliminated, and only those required for trunk lines and special traffic are retained. THE FUTURE. ‘ ‘ My opinion is that, oven on an annual cost basis, if a manual system were to ‘ prove in ’ by a margin of, say, 5s per lino per annum, calculated on to-day’s costs, it would be advisable to pay this amount, or possibly oven more, depending on the future possibilities to obtain other advances of automatic working for the future. On thw latter point there are differences of opinion. Some prominent telephone men require a definite advantage on the annual cost before adopting an automatic system. My conclusion is that under conditions os they exist in Australia the other advantages of automatic working are worth buying at a somewhat increased annual cost. It is now accepted by the telephone world that the future telephone switching mechanism for large networks must be automatic. This tendency is shown in the action recently taken in England, Germany, Bavaria, Austria, and Holland, in all of which -countries automatics are either in use or are contemplated. “ As the result of my inquiries, therefore, I am led to make these recommendations : (a) That when complete new equipment is required in any exchange in any multioffioe network, tenders shall be invited only for fnll and semi-auto-matic equipment. Cb> That in the case of existing

manual equipment requiring extension, close consideration shall in every case be given to the question of where it is better to i natal a separate automatic or semi-automatic equipment instead of extending the existing manual equipment. (c) That in other exchanges in which it is calculated that more than 500 Lines will be connected within five years, alternative benders shall be invited for common batteries and full and semi-automatic equipment.”