Install sffview by entering the following commands in the terminal:
sudo apt update sudo apt install sffview
Description:
Structured Fax File (SFF) Viewer
sffview is an X11 viewer for SFF files. SFF is the "Structured Fax File" format for group 3 fax documents which ISDN cards supporting the CAPI specification expect and create.
Homepage: http://sourceforge.net/projects/sfftools/
Version: 0.5.0-2
Section: universe/graphics