The Australian Communications and Media Authority is seeking public comment on proposed variations to digital television conversion schemes to enable the staggered, region-by-region switch-over to digital television. The Commercial Television Conversion Scheme 1999 and the National Television Conversion Scheme 1999 set out the process by which analog to digital conversion is to occur. The schemes apply to commercial and national (ABC and SBS) television broadcasters. ?The proposed variations to the schemes are intended to assist the implementation of the Government?s digital television switch-over timetable,? said Chris Chapman, ACMA Chairman. The proposed variations follow amendments made to the Broadcasting Services Act 1992 in December 2008. Before finalising the proposed changes to the schemes, ACMA is calling for comments on the draft variations. The closing date for comment is Friday 20 February 2009.