Adobe Acrobat 7 Professional - Manual (Page 261)

Marking up AutoCAD drawings (Windows)
You can add comments and markups to a PDF document that was created from an
Autodesk AutoCAD drawing. The review initiator can import these comments into the
original drawing to assist the revision process. (See
Exporting markups to an AutoCAD
drawing .) Acrobat includes several tools that are suitable for reviewing plans and designs
in the Drawing Markups toolbar.
Note: AutoCAD drawings must be converted to PDF in AutoCAD by using PDFMaker.
(See
Converting Autodesk AutoCAD files (Windows) .)