 <p>I realise this is an old question and you maybe already have an answer (or have no need for one now) but it looks like it's RML-1, assuming my searches were correct.</p> <p>I first found <a href="http://www.digitalfabrication.net/tutorials/AADPL_CNC_Manual_2010.pdf" rel="nofollow">this</a> which showed very similar code to your example. It mentions ArtCAM and output for the MDX-540, a Roland machine.</p> <p>Searching Roland's milling machines for information was a bit useless, but going through their <a href="http://www.rolanddg.com/product/3d/3d/mdx-540/spec.html" rel="nofollow">3D products for the MDX-540</a> mentions that the control command sets is "RML-1 and NC codes".</p> <p>Then searching for RML-1 gives a <a href="http://mlab.taik.fi/paja/wp-content/uploads/2011/01/RML1_Command_GuideENVer100.pdf" rel="nofollow">result for a PDF manual</a>.</p> <p>Reading that PDF it looks like the single letter commands are "Mode 1", the ^ is used to select Mode2 and the 2 letter commands are Mode2 commands. !xx commands are common to both Mode1 and Mode2.</p> <p>^PR sets the movement to relative mode. ^PA sets the movement to absolute mode. Z moves.</p> <p>Looking at your code sample it appears as if most positions are absolute and you'd need to re-write them all.</p>