You may specify document conversion explicitly by setting a pre-process of type FFEXTERN and a process of FXCVRT, with a non-zero queue number to match the one set in the FFEXTERN program for the conversions to be performed. This requires a non-zero queue number to be specified on a $fax_pre-process command in each FS file.

The recommended method, however, is to use the $convert_types command in the configuration file. This takes a number of document-type keywords, and automatically places FS files referencing these types into the PREPROC directory to be picked up by FFEXTERN. It also creates a virtual $fax_pre-process command for FXCVRT with a queue number of 0. When you use this technique, the queue number set in FFEXTERN must be 0.

FFEXTERN will only make one attempt to preprocess items of type FFEXTERN for each FS file, by matching the queue specified on the $fax_pre-process command, the document checkboxes checked for that queue in FFEXTERN, and any of the document file types in the FS file. After this, additional $fax_pre-process commands and FFEXTERN queues will be ignored.