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ISDN is used for the carriage of information such as voice, data, high quality sound, text, still images, and video over the public switched telephone network and DDAS is an access service for the domestic carriage of data. The service can combine the use of a customer access line with management to ensure high quality data transmission.

The ACCC considers that both the DDAS and ISDN services are becoming outdated, legacy technologies. Since the previous review their use has declined in regional areas.

Furthermore says the regulator, an extension of the services for 12 months will provide an appropriate transition period for users to migrate to alternative technologies or services in regional areas.


The ACCC also notes that the implementation of a national broadband network (NBN) potentially alters the competitive landscape of business data services in regional areas.

However, the ACCC admits that it does "not know the extent and precise impact of a NBN – in terms of availability of wholesale business data services – nor how the migration to the NBN will be managed".
The ACCC says it "expects that these issues will become clearer when the NBN process is finalised by the government".