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

The exchange equipment for the automatic programmes for the whole of the period was imported, first from AEC, Chicago, and after 1925, from five UK manufacturers. Equipment supplied between 1912 and 1915 used 'uncovered' switches with relays mounted wherever practicable and with Keith line switches used as preselectors, but by 1919, when the next exchanges were supplied, there had been considerable development with many circuit improvements and upgraded constructional detail. In 1935 the BPO adopted a new type of selector, designated 2000 type, chosen from a number of designs by British manufacturers. It was a complete re-design of the bi-motional switch concept to give a more economical and reliable switch and was adopted by Australia with first installations in 1938. The equipment included a Discriminating Selector Repeater (DSR), providing extra facilities, including direct switching to other exchanges in the same main exchange area and direct switching to the trunk exchange on level 0. As this switch was not used in the UK it may have been specifically designed to meet Australian needs, but apart from this, 2000 type equipment was to BPO specifications and standards. Overall, from 1912 to 1945, exchange design work was carried out by the manufacturer and there was thus little original contribution to automatic exchange technology by Australians. There were, however, local initiatives, generally small refinements, many of which have not been documented.

In 1901 telephone service was available in a scattering of country towns, as policy under the colonial governments had been to open an exchange if more than a specified number of applications were received, usually around fifteen. Further exchanges were opened as demand increased until by 1930 nearly every country town had an exchange ranging from 10 line pyramid boards to 200 line floor positions. Although Geelong was the first Australian automatic exchange in 1912, by 1940 only five more country exchanges had been converted to automatic -Cairns 1932, Canberra 1937, Rockhampton 1939, Tamworth 1939 and Wagga 1940.

Limited technology and high costs hampered the growth of rural telephones for many years and, apart from relatively short lengths of line near the exchange, the subscribers had to provide or pay for the remainder, and usually erected the lines themselves -'part privately erected' or PPE lines. Various cost cutting measures were permitted on these lines, including the use of iron wires, earth return circuits and low ground clearances, providing multi-party lines with code ringing and no privacy. The subscribers' costs were least in a system of numerous small exchanges, which reduced the length of PPE line required, but overall costs were least in a network with a smaller number of exchanges. In general the compromise went in the direction of additional exchanges but, in order to obtain 24 hour a day service, some PPE lines were built past small exchanges to larger ones. The end result of all these factors was a disorderly network of privately constructed lines which, however, for several decades provided at least a basic service.

Australian Academy of Technological Sciences and Engineering