For some drafting standards, AutoCAD Mechanical toolset supports more than one revision of the standard for symbols.
For example, when the drafting standard is ISO, AutoCAD Mechanical toolset supports ISO 13715 - 2000 edge symbols as well as ISO/DIS 13715 - 1984 edge symbols. Since the options supported for one revision differs from the other, selecting the drafting standard alone is not enough; you must select the correct revision of the standard as well. The AM:Standards tab of the Options dialog box lists the revisions below the symbol, as shown in the following figure.
If the revision you need is unavailable, insert the standard first.
In some cases, when the selected drafting standard doesn’t support a symbol, you can insert the symbol from another standard. For example, the GOST standard does not support datum target symbols. However you can insert the ISO datum target symbol and use it in a GOST drawing.