pbmtog3

Updated: July 2002
Table Of Contents

NAME

pbmtog3 - convert a PBM image into a Group 3 fax file

pbmtog3 [-reversebits] [-nofixedwidth] [pbmfile]

This program is part of Netpbm.

pbmtog3 reads a PBM image as input and produces a Group 3 fax file as output.

-reversebits: This option causes the output to have the bits in every byte reversed so the least signficant bit becomes the most signficant bit. Apparently, there is some ambiguity in transmission protocols so that the bits get reversed on transmission, and this compensates for that. If you get a whole bunch of "bad code word" messages when you try to read the G3 file (e.g. with g3topbm, try using this option. Note that the output is not G3 when you use this option.
-nofixedwidth: Most fax machines expect the image to be 1728 columns wide, so pbmtog3 cuts the output to this width by default. If you want to keep the width of the original image, use this option.
This option was new in Netpbm 10.6 (July 2002). Before that, pbmtog3 always kept the width of the original image.

The standard for Group 3 fax is defined in CCITT Recommendation T.4.