If you define a field but no data is extracted or the associated action is never carried out then there are several possible explanations:

Tag not found

Red diamond bullet Check that the tag (or at least the start of the search string) is located in the designated area.

Red diamond bullet An inappropriate page range may have been specified in the Searching page of the Field dialog (select Fields|Edit... or press Ctrl D keys).

Red diamond bullet Incorrect set of font characteristics specified in the Searching page of the Field dialog.

Red diamond bullet The field may be a sub-field of a field that was not found. Note that sub-fields are assumed to be in a fixed position relative to their parent field.

Inappropriate symbolset

Red diamond bullet Check that the source has not been reconfigured since the field was defined; there is a drop-down list of source types on the General page of the Configuration (press f8 key) dialog:

Source Type

Typical symbolset

Windows driver

HP3 – the character codes are adjusted by 3 so that a "D" in the file is translated to "A", etc.

RedTitan DDF (PrePrinter)DDF 'printer' icon

none – no translation is required.

RedTitan Datastream Converter

9700

Other

(none)

Red diamond bullet Test the symbolset: define a tagged field by right-clicking on a piece of text and choosing New tag...; if the symbolset is correct the identical text will appear Tag string box on in the 'Searching' page.
If it is incorrect, choose a different symbolset in the General page of the 'Configuration' (f8) dialog and try again. For example, custom PCL output (Source Type set to 'Other') usually requires no translation but a few drivers require symbol set HP-1 (adds 1 to each code).
You may need to use a character recognition database in some cases: see EEfonts iconEEfonts.

Extracted data is mistranslated

Red diamond bullet Inappropriate symbolset – see About symbolsets.

Tag names appear as box characters

Red diamond bullet Some drivers assign arbitrary codes to the characters as they occur in the document, so there is no way of calculating the appropriate translation. In these cases it is worthwhile changing the font used in the original document to be one of the printer-resident fonts (e.g. CG Times), so that the normal codes will be used.