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)
When trunk carrier cables began to be introduced into the network, they were fitted with gas pressure alarm systems to both give an early indication of a fault in the cable sheath and to act as a protection against moisture entry through the faulty sheath. Initial practices followed those developed by the AT&T Company, but these were progressively developed to meet Australian requirements leading to considerable pioneering work. An account of the gas pressure alarm system on the Melbourne-Seymour cable[55] refers for instance, to the development of new sealing techniques as a result of problems encountered, modification of the AT&T type contractor to include test terminals, the later re-design of the terminal, experiments to correlate the loop resistance of a cable pair with the temperature of the cable, and experiments designed to improve the location of a relatively small hole in the cable sheath.During the nineteen fifties the use of gas pressure alarm systems was rapidly extended to include not only trunk and junction cables, but also most of the subscribers' main cable network. This development, combined with extensive work to reduce cable sheath deterioration, resulted in greatly improved system performance. The introduction of coaxial cables around 1960 brought new challenges to the engineering of gas pressure alarm systems because of the much lower resistance of the cables, not only to gas flow but to water flow, should water in significant quantity penetrate the sheath. These issues resulted in a review of the principles underlying gas pressure alarm technology as the basis for developing appropriate systems as set out by Pollard and Ross.[56]
Organisations in Australian Science at Work - Australia Post: set up
People in Bright Sparcs - Pollard, J. W.; Ross, N. G.
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Australian Academy of Technological Sciences and Engineering |  |
© 1988 Print Edition pages 588 - 589, Online Edition 2000
Published by Australian Science and Technology Heritage Centre, using the Web Academic Resource Publisher
http://www.austehc.unimelb.edu.au/tia/567.html