QuickLink software was early telecommunications software developed by Smith Micro. QuickLink II was a popular fax/data and voice communication software for DOS, Windows & Macintosh. Its native format was graphics format with the extension QFX, based on TIFF.
QFX files are based on TIFF, early versions begin with "
51 4C 49 49 46 41 58" or "QLIIFAX" in ASCII. Later versions are TIFF's with the ascii "QL2FAXW" at byte 8.