Standardize the PDF output of drawings
Use TrueType fonts
All text in the drawings must be in TrueType format, otherwise the hotspot feature won't be able to read the references.
AutoCAD's older shape files (SHX format) won't work.
Create the text using one of the TrueType fonts or styles (in the standard Width Factor 1.0). Existing text can be altered to use a TrueType font. Then the classic commands EXPORTPDF, PUBLISH and PLOT will publish, using the internal AutoCAD print PDF-driver (DWG To PDF.pc3) standard "text-based" PDF files.
Why aren't SXH fonts recognized in PDFs?
Text based on SHX fonts in AutoCAD will be exported as vectors, and will be unreadable in the PDF.
This is because the characters in SHX fonts are plotted as pen strokes. While an “E” looks like an “E” on screen, it is actually one vertical line and three horizontal lines. Once the character definition is lost in the PDF file, it cannot be extracted.
To find out if the text in your files is readable, open the PDF file and try to select the text on screen. If you can select it, it will convert. If you cannot select it, it's a graphical object and will not be usable. You'll need to convert your fonts to TrueType fonts.