It is usually at the discretion of the drafter if a detail will be required. If he or she feels that the item is too small to properly fit dimensions and notes, the item can be enlarged for annotation purposes. 

 

                        Detail call-out                                                Enlarged detail 

As with sections, the line in the bottom half of the circle indicates that the detail call-out and the enlarged detail are on the same drawing.

If the detail call-out was on drawing 1 and the enlarged detail was on drawing 3 the symbols would look like this:

 Detail call-out(on dwg 1)      Enlarged Detail title (on dwg   3)

The following detail title symbol will be used for this part of the course 
(Drafting Core)


Detail call-out and title symbols will be provided for you as blocks for the rest of the program.
Note: Symbols differ between Architectural and Mechanical drawings.