The G-code system used in Australia appears to be identical to
the ShowView system used in Europe. ShowView is related to (very similar,
but slightly different) VideoPlus in the UK, which, in turn, is based
on VCR+ used in the US. All of these systems are made by Gemstar.
All of these systems have been reverse engineered to determine their algorithms
and tables, up to (and including) codes of six digits length. The mechanisms
for seven and eight digits haven't been determined, although you can decode
parts of 7 and 8 digit codes (for example the day).
Code to encode and decode showview codes (and hence Australian G-code) can
be found at
ftp://ftp.sdt.net/private/minder/showview.zip
The program asks questions in German, but this is easily figured out.
The author, Danial Minder, also has a little text file (originally from Dave
Hosgood), with some interesting trivia.
Daniel Minder also has a web page, where you can type in ShowView codes
and get back the decoded results. The page is in German:
http://www.sdt.net/minder/showview.htm
If you have a PalmPilot, there is also a program to generate ShowView codes:
http://www.pilotzone.com/files/showvu.zip
The videoplus code, the UK system, can be found from Steve Hosgood's site at:
http://iiit.swan.ac.uk/~iisteve/steve.html
All of this is based on work done in 1991, 1992 on the US VCR+ plus
system. The papers describing the original crypt analysis, the VCR+ algorithm
and original VCRplus program can be found at Curt Welch's web site. Curt
also has a link to GemStar's page.
There are several news articles describing why the 7 and 8 digit code mechanism
hasn't been deciphered yet, together with some suggestions on how this might
be done:
http://search.dejanews.com/getdoc.xp?AN=212076640
http://search.dejanews.com/getdoc.xp?AN=212080764
http://search.dejanews.com/getdoc.xp?AN=211873470
Jamie (jho...@mpx.com.au)