Applies to: ZuperFax Gateway 7.0, 7.1
Symptoms
When a release-of-information packet longer than 47 pages is faxed, page 48 arrives blank and the remaining pages
are shifted by one. The transmission log shows T.30 MCF for every page, so the sending side reports
success.
Cause
Scanned charts are stored as multi-page TIFF with CCITT Group 4 compression. A handful of scanners write
FillOrder=2 (least significant bit first). ZuperFax reuses its decoder state across pages, and the
fill-order flag was only read for the first 47 IFDs because of a fixed-size cache that dates back to ZuperFax 3.0,
when nobody imagined a 48-page fax. Page 48 is decoded with the wrong bit order, yields no valid run lengths, and is
sent as white.
Resolution
Apply cumulative update CU7 for ZuperFax Gateway 7.1. As a workaround, set
HKLM\SOFTWARE\Zupermicro\ZuperFax\7.1\Render\NormalizeFillOrder (DWORD) to 1 and
restart the ZuperFax Render service; packets are re-encoded with FillOrder=1 before transmission.
More information
Zuper Micro Man personally inspected page 48. It was, in fact, blank.