If the format of a specified FILE is not recognizable either explicitly (by its extension) or implicitly (by its content), specify its FILETYPE in the FILE tag itself:
where ext may take one of three values:
For example, a file output by printer with extension PRN could be placed in an IDF document using
<FILE FILENAME = "FRED2.PRN" FILETYPE = "PCL" PAGE="4"/>
Plain text files – which usually have extension ".TXT" – are normally specified as FILETYPE="TEXT". Due to the lack of page-breaks in TXT files, however, it is sometimes useful to specify FILETYPE="PCL" instead: see Notes on text.
The default file-type for unrecognized files is PCL5.