NT's finally updated its primary driver training manual, "The Road Users' Handbook" (Edition 2, 07).  I suggest, as always, that folk regularly read their jurisdictions driver handbook in order to keep up to date with rules generally, and to refresh on some of the practical advice given.

In relation to this and similar websites advocacy of speed derestriction, if you download the book from the provided link (Right click, choose 'save as') you will see the derestriction diagram (//) has been removed completely from NT's manual.

That is appropriate, BUT the road authority *must* remove ALL speed derestriction signage from the NT road network without fail, this can take years. 

A key reason 'why' has to do with the signs contracted International meaning, where it is held in various United Nations Conventions on Road Traffic, Road Signs and Signals as sign catalogue number C,17(a) - representing; "End of all local prohibitions imposed on moving vehicles", hardly - 'default speed limit 110km/h'.

Australian Standard (National Metrology) 1742.4 of 1999 lists the sign with the same outcome 'to signal that NO speed limit applies to the road beyond the sign', but is catalogued as an R4-2.

NT Road Users' Handbook, Edition 2, 07.  Pdf 2.16Mb:-http://www.ipe.nt.gov.au/whatwedo/mvr/roaduserhandbook/handbook.pdf

JP - Mot Adv-NSW