If two or more dwellings are on a single block, but have separate titles (eg, strata title units) and therefore individual addresses, then NBN Co will happily connect them all.
But if you put a granny flat or other habitable outbuilding in the backyard, only one NBN connection is possible.
Furthermore, according to NBN Co's Residential preparation and installation: Single Dwelling Units (SDUs) and Multi Dwelling Units (MDUs), "The NTD and NTD enclosure, along with its default PSU (PS/S or PS/OBB), must be installed in the same building as the main electrical meter box or distribution board. The nbn equipment is only certified for connection to customer cabling (structured wiring), which is entirely enclosed within the same building."
So there is a workaround for situations where members of the same family — eg, adult children — are living in the outbuilding, as you would expect everyone involved to come up with a way of equitably sharing the bill just as if they were all living in the main building.
But what about the situation where the granny flat is occupied by a genuinely separate household?
Senator Steele-John thinks the present rules aren't good enough.
"Different people have different living arrangements and different Internet requirements. This is an unprecedented service limitation imposed by NBN Co that has not been an issue with previous technologies, such as ADSL and landline telephone services," he said.
"It is not reasonable to expect someone who is renting a granny flat, or even extended family living in separate dwellings at one address, to have to share a single NBN connection. It is completely out-of-touch.
"Given connection to the NBN will eventually be mandatory for users to access the Internet in Australia, NBN Co must be flexible to the changing living configurations we are seeing as our urban centres grow.
"The increasing trend towards multiple dwellings per title to accommodate population growth and demand for rental in our major cities and urban centres must be met with improved service accessibility by NBN Co.
"Australians deserve a fit-for-purpose national broadband network to ensure we remain competitive in our increasingly digital world, and that includes the possibility of more than one connection per title."
Senator Steele-John noted that the Senate had passed an Australian Greens motion calling on the government to deliver a fit-for-purpose NBN that meets the needs of all Australians, including those living in outbuildings and granny flats.
Whether that results in any changes to the rules remains to be seen.