SDF 2 files can only be imported (and exported). They cannot be accessed using Data Connect. SDF 3 files use Data Connect.
To import SDF 2 files
To create a new AutoCAD layer, click Create New Layer. In the New Layer dialog box, specify a name for the new layer.
To select the code from a list, click Select Coordinate System.
To create a new table or field, click Create New Table or Create New Field.
In the Define New Object Data Table dialog box or Define New Object Data Field dialog box, specify the information for the new table or field.