sentences:  The "Broadcasting Legislation Amendment (Digital Television) Act 2006" permitted television networks to launch digital multichannels, provided that they are broadcast exclusively in high definition.Although originally expected to be the first free-to-air commercial television channel introduced to metropolitan areas since 1988, the surprise launch of Seven Media Group's HD offering, 7HD, on 15 October 2007, two months before transmissions were scheduled to begin, meant that Ten HD was launched as the second high-definition multichannel in Australia.PBL Media announced the creation of a similar multichannel, 9HD, on 27 September, which was launched on 17 March 2008.