The heavyweight telecommunications company said the extension would be undertaken following 12 months of testing and investigation by Telstra Research Laboratories.
Telstra CountryWide boss Doug Campbell said "extensive research and statistical sampling" by the carrier revealed voice and data quality on telephone lines which also carry ADSL services remained acceptable to "at least" 4 kilometres in line distance from an ADSL-enabled exchange, "depending on the cable type and wire gauge". This was at least 500m more than the previously accepted limit.
Campbell said the move would impact most significantly on outer metropolitan and regional areas and was one of a series of measures designed to improve ADSL reach from 75 to 90 percent of services over the next three years.
"Telstra has been striving to put ADSL within reach of more households and businesses across Australia and we have now fully assessed the new transmission limit to make this possible," he said.