Batch convert

I'm looking for software to batch convert from AutoCAD 2006 DWGs to 2000 DXF, 2000 DWG, and 3ds. I also want it to convert the 3ds back to DXF.
Is there such an animal out there?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.