Chapter 8
I Part 1: Communications
i Before the Telegraph
ii Electrical Communication Before Federation
iii Federation to the End of the Second World War
iv Post-war and on to 1975
v 1975 ONWARDS
II Epilogue
III Part 2: Early Australian Computers And Computing
IV Acknowledgements
References
Index
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Post-war and on to 1975 (continued)
In developing the system extensive design and innovation to overcome a wide range of problems were undertaken in Head Office and in each of the States. As an illustration, since large network savings were expected from crossbar, both because of the independence of numbering and switching and of the alternative routing capabilities which were available, tandem locations appeared to have an important influence on costs. In order to establish network design parameters, a Traffic Dispersion Recorder was developed in Sydney, using some techniques from the American automatic toll ticketing equipment, to record details of the destinations and origins of a sample of calls from individual step by step exchanges -H. Freeman played an important role. In an early application of electronic computers to telecommunications engineering in Australia, and indeed one of the first in the world, the information from the Recorder was processed by the SILLIAC computer to produce a matrix of existing point to point traffic and to forecast future traffic. This information became an input to a programme known as 'Comet' (Calculation of Most Economical Tandems), which produced estimates of junction quantities and costs for specified tandem configurations. Somewhat unexpectedly, it showed that an alternative routing system had considerable ability to adapt and make the best use of whatever tandem network was provided and consequently selection of tandem numbers and location was not a critical factor.In Melbourne, traffic data for the crossbar tandem network was obtained by a locally developed call dispersion recorder, rather simpler than the Sydney equipment, but able to obtain larger samples because holding times were not measured. The tandem network developed was substantially different from that in Sydney, reflecting the heritage arising from almost a century of different approaches to network planning, with four tandem locations to serve the pre-ELSA unit fee area, all located towards the centre of the network and each employed three specialised switching stages. The outer areas were to be served by five smaller tandems each with X and Y stages.
Foreshadowing quite revolutionary changes in international communications, in October, 1957, HF signals from the USSR Sputnik, the world's first man-made satellite, were picked up by OTC engineers and excited considerable interest. Five years later, Australia was amongst the first group of countries which began to address the problems of international communications using satellites and in August of that year, along with ten other signatories, became a founding member of the Interim Communications Satellite Committee (ICSC) which functioned as the initial policy decision making body of INTELSAT. As a member of ICSC, OTC developed proposals relating to public telecommunications standards for satellites resulting in the following general concepts being adopted:
- ICSC should formally adopt CCITT standards and publicise the fact that it was offering service to those standards
- to achieve the former standards, ICSC should specify a 'standard' satellite earth station at or near the top of known technological performance capability, in order to maximise the amount of derived satellite capacity
- the basis for the standard unit of space segment charge should be related to the satellite capacity required to provide a CCITT standard telephone circuit between two standard earth stations as defined above
Organisations in Australian Science at Work - CCITT (International Consultative Committee for Telephony and Telegraphy); Overseas Telecommunications Commission (O.T.C.)
People in Bright Sparcs - Freeman, H.
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Australian Academy of Technological Sciences and Engineering |  |
© 1988 Print Edition page 575, Online Edition 2000
Published by Australian Science and Technology Heritage Centre, using the Web Academic Resource Publisher
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