Technical information

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Fax Imaging
Fax Imaging
Multi-page Tagged Image File Format (TIFF) is the basic underlying file format used to send all faxes with VSI-FAX.
However, you do not have to restrict your faxing to just TIFF files. VSI-FAX uses programs called formatters to
convert common file types to TIFF files so that they can be faxed. This conversion process is what is referred to as
"imaging."
How does VSI-FAX know which formatter to use with which file extension? When the VSI-FAX server is started, one
of the tasks performed on start-up is to compile a list of file types that can be handled by the imaging engine. This list
is constructed in the following manner:
1. First, VSI-FAX looks in the formatters.lst file for an entry that associates the file extension and formatter
(for example the entry doc:doctotif.exe:o: indicates that all files with a .doc extension should be
imaged using the DOCTOTIF formatter). All formatters.lst entries are added to the list.
2. Then, VSI-FAX queries the list of internal formatters (see Types of formatters
for the definition of an "internal"
formatter) and adds these entries to the list.
3. Next, VSI-FAX queries the operating system to determine if there are any file type associations that are
handled at the OS level. When the fax server is a Windows OS, this list will be the list found under Tools >
Folder Options > File Types. When the fax server is a Unix OS, it will look to see if an imaging server has
been configured. If an imaging server is configured, the file type available on that system will be retrieved. All
of the available file type associations are then added to the list.
Note
Once the server starts, you can check the file types than can be handled by entering the following
command:
vinfo -D -v filetypes | more
The result is a list of the file type associations recognized by the VSI-FAX server. From this list, you can
tell whether a standard formatter or a DDE print command will be used to image the file. When executed
on a Unix fax server, this command will also list the DDE associations for an imaging server if one is
configured.
4. When a fax request is submitted to the server, VSI-FAX determines which formatter to use when imaging the
file by performing the following checks:
Does the file extension (the characters after the "dot" in the file name) match any of the file types on
the list created at start-up? If so, use the formatter specified with the extension.
If the file has no extension or one that VSI-FAX still cannot associate with a formatter, VSI-FAX will try
to determine the file type by examining the first 256 bytes of that file. If VSI-FAX determines that it is a
PostScript, PCL, or TIFF file, it will image it using the appropriate formatter. If VSI-FAX cannot
determine that it is a PostScript, PCL, or TIFF file, it will image the file as plain ASCII text.
Types of formatters
There are five types of formatters used by VSI-FAX. While differentiation between types of formatters is a construct
that is internal to the VSI-FAX program and not a term you will emcounter in the program, knowing the type of the
formatter that you want to use will help you determine how and under what circumstances it is accessed by VSI-FAX.
Native formatters : VSI-FAX has support for specific file types. This support is internal to the server and thus
provided on all platforms. Native formatters can process .tif, .fax, .pcx, and .bmp files.
Internal formatters : these formatters come preconfigured and do not require any additional set up on your
part. The internal formatters can be identified by using the -F switch on the VFX command line. They are