Federation to the End of the Second World War (continued)

order wire working to B position operators; lamp signalling junctions to B position operators; ring down junctions to A position operators; tandem switching via special positions at City

As tandem switching caused operational difficulties, it was policy to provide direct junctions between any two exchanges with more than 10 calls in the busy hour, or about 0.4 Erlangs, although this small amount of traffic necessarily resulted in many inefficient routes. Nevertheless there was a considerable amount of tandem switched traffic as a consequence of the large number of small exchanges.[11]

The history of the Melbourne network over the same period was slightly different, mainly because of the differences in exchange sizes. In 1901 there were 4804 subscribers connected to 13 exchanges but 92 per cent of these were connected either to Central or to four other rather large exchanges, and the amount of tandem traffic was thus much less. At the time, the Central exchange was a 3600 line branching multiple installation, an obsolete design, but incoming B positions had been added. Evidence to the Royal Commission disclosed that capacity had been extended to 4800 lines by adding twelve non-multiple one hundred line boards, while a 4800 line branching multiple board had apparently been commoned across the whole exchange to give a quite unconventional solution, involving considerable technical ingenuity, in order to provide a reasonable level of service. Problem exchanges were Hawthorn and Malvern, which had been extended with non-multiple boards, resulting in installations of almost unworkable size. In 1911, CB exchanges were installed in Central, Windsor and Hawthorn and unrecorded improvements were made to Malvern, together resulting in a first class manual network and, starting in 1914, the remaining small manual exchanges were gradually replaced.[12] The smaller cities did not have large manual networks and thus did not generate problems additional to those encountered in Sydney and Melbourne.

Although considerable effort was expended on improving and extending the line plant in the years following Federation, the Royal Commission reported that much was in need of quite urgent attention. For instance, evidence was given that in Sydney, only 40 per cent of the lines were metallic circuit, while in Melbourne only two lines out of 1,600 at the Central exchange and 200 out of 1,600 at the City exchange were metallic. Other capital cities were in a somewhat better position and Hobart, with a CB exchange, had a fully metallic network. The Commissioners expressed the opinion that 'to obtain an efficient telephone service, the installation of metallic circuits is essential in large networks, as such circuits minimise induction and consequent confusion in the transmission of conversation', and recommended that funds be provided to allow the underground system to be completed in all large cities.

An Ericsson wall telephone was generally used with magneto exchanges and when CB exchanges were introduced, a corresponding telephone, smaller in size because of the absence of the magneto and batteries, was introduced. The next requirement was a dial instrument to work with automatic exchanges and in each case the instruments were imported, with the workshops undertaking any necessary modifications and maintenance. However, this situation was not accepted without query and the 1910 Royal Commission examined the technical officers of the Department and the representative of the Amalgamated Society of Engineers concerning the advisability of the Department manufacturing its own telephones but, having regard to both costs and the relatively small Australian market, the Commissioners found the proposal uneconomical at that time. They recommended, however, that the matter be kept under review and if financial prospects of Australian manufacturers of telephones improved, consideration could be given to a government factory to produce also cables, wire, switchboards and insulators. They noted, too, that such a factory would provide an excellent training school for technical staff. Such a development did not occur but the First World War gave a stimulus to local manufacturing, including the production by the Department's own workshops of a range of items no longer available from overseas. One enduring development saw Metal Manufacturers producing copper wire at Port Kembla in 1918 and five years later, begin delivering lead covered, paper insulated cable to the Department.[13]

Australian Academy of Technological Sciences and Engineering